* [MLv2] Add `preview-expression` to eval an expression on sample data

This is needed to show the previews in the UX for the combining columns
epic #39977.

Fixes #39979.

* [MBQL lib] Add "Combine columns" drill-thru

This is following the original plan of using a drill for this. It's hard
to combine that with the "preview" functionality.

See [thread](https://metaboat.slack.com/archives/C06P22KS4JH/p1712264174056569)
for discussion of how we might approach that issue.

Fixes #39978.

* [MBQL lib] Add "Combine columns" drill-thru

This is following the original plan of using a drill for this. It's hard
to combine that with the "preview" functionality.

See [thread](https://metaboat.slack.com/archives/C06P22KS4JH/p1712264174056569

)
for discussion of how we might approach that issue.

Fixes #39978.

* [MLv2] Add `preview-expression` to eval an expression on sample data

This is needed to show the previews in the UX for the combining columns
epic #39977.

Fixes #39979.

* [MLv2] Add `preview-expression` to eval an expression on sample data

This is needed to show the previews in the UX for the combining columns
epic #39977.

Fixes #39979.

* Revert "Merge branch 'mblib-preview-expressions' into combine-columns"

This reverts commit dac17f84aaae09906a206106290f7f58dea659bd, reversing
changes made to 2934fab19db495ca8104801d41bc8aba457e401f.

* Revert "Merge branch 'mblib-preview-expressions' into combine-columns"

This reverts commit 2934fab19db495ca8104801d41bc8aba457e401f, reversing
changes made to 6a43c22e78fb616c7ac0b024811b2989a1ae0f20.

* Revert "Merge branch 'mblib-preview-expressions' into combine-columns"

This reverts commit 6a43c22e78fb616c7ac0b024811b2989a1ae0f20, reversing
changes made to 2257333a8ae69f0c9a6f6fdf0c8f5d837263f97a.

* [FE] "Combine columns" drill thru (#40082)

* Type Section['icon'] properly, including the hack for summarize section

* Add combine columns section

* Add types for combine columns drill

* Add combine columns drill component stub

* Mock combine columns drill

* Add component stub

* Encapsulate typing hacks

* Extract CombineColumnsDrill

* Extract ColumnAndSeparatorRow

* Improve naming, add button to edit separators

* Translate string

* Improve styling

* Separator input

* Handle removing columns

* Rename lib.ts to utils.ts

* Implement onSubmit

* Add getNextColumnAndSeparator

* Use form for a11y

* Handle vertical overflow

* Handle horizontal overflow

* Extract formatSeparator

* Use proper translations

* Adjust min/max sizes

* Fix scrollbar being unnecessarily shown

* Display source column name

* Avoid serializing the entire column and putting it into DOM

* Use module.css extension

* Format code

* Improve a11y

* Mock combineColumnsDrillExpression and previewExpression

* Add Preview component

* Move preview logic to Preview component

* Style Preview

* Format code

* Move styles to CSS modules

* Update UI to latest designs
- move "Add another column" button
- remove "Separated by X" button
- always show separator inputs

* Remove displayInfo mock

* Add asReturned

* Update CombineColumnsDrillThruInfo

* Integrate new way of working with combine columns drill

* Fix generating expression names

* Integrate drill with click actions

* Integrate new preview workflow

* Revert "Update UI to latest designs"

This reverts commit cda039dffe9d452c0866f63800e2e887a540fe67.

* Use previewExpression interface correctly

* Use new preview_expression API

* Make sure columns are created with original query and stage index

* Extract usePreview and handle preview errors

* Update popover title

* Move add column button

* Fix outline being cut off

* Style preview label as per design

* Format empty separator

* Make preview scrollable

* Use project convention

* Simplify ScrollArea usage

* Use ScrollArea in CombineColumnsDrill

* Update comment

* Remove Lib.previewExpression

* Clean up the preview after removing Lib.previewExpression

* Implement getPreview

* Change default column preview to 'text'

* Remove usePreview hook which is no longer in use

* Rename Preview to Example

* Use different placeholder for separator input

* Add whitespace placeholder

* Add ColumnPicker boilerplate

* Export Input

* Use QueryColumnPicker for ColumnPicker

* Pass width to AccordionList

* Add sequences popover events with tippy

* Remove unused ColumnOption helpers

* Add testid to Example

* Add e2e test for combine column in header

* Select content of separator input on focus

* Reduce padding on example

* Add monospace variant to Text

* Use monospace variant in Example

* Use monospace font in textinput

* Match faux-select label styles to our TextInput label styles

* Add missing color

* Remove !important

* Use pre whitespace so consecutive spaces show up

* Remove empty default

* Add example for boolean

* Remove !important

* Use should.have text over contain

---------

Co-authored-by: Romeo Van Snick <romeo@romeovansnick.be>

* Remove duplicated code

* Export useMantineTheme from metabase/ui

* Use useMantineTheme instead of reading theme directly

* Remove setTimeout in popover

* Use plain t instead of jt

* Move Popover dropdown sequence hack to metabase/ui

---------

Co-authored-by: Braden Shepherdson <braden@metabase.com>
Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>