Make k-means grouping work with less than 5 rows

Fixes: https://github.com/metabase/metabase/issues/4684

Fix Firefox Content-Security-Policy warnings

Dont send pulse if all cards are empty (continues #4184)

* QB modes, actions, and drill throughs.

* Refactor drill throughs + misc bug fixes

* Port sort action to drills

* Smarter 'view this/these' name

* Scalar hover state

* QB actions: don't skip action selection screen unless the action is marked as 'default'

* Fix flow errors

* Fix drills

* Show "This X's Ys" for FKs

* Prevent qb from uneccesary push states

* Don't show (fk) breakout fields that have already been broken out

* Fix 'drill into this' unit

* Cleanup timeseries footer

* Cleanup qb selectors

* Namespace all qb actions

* Make modes dependent on previously run card

* More timeseries footer cleanup

* Fix table crash

* Make breakout legend clickable

* Fix datagrid pivot test

* Flow + lint

Fix connecting to SQL Server DBs with passwords with special characters

Throw a helpful error if #metabase_files channel is missing when sending message to Slack

[ci drivers]

Merge release 0.23.1

Use JDBC metadata fn to fetch MATERIALIZED VIEWS (credit: @lindsay-stevens)

Make sure FieldValues get deleted if cardinality passes threshold

Add All Options date filter to dashboard

fix #3781