Append indexes to duplicate expression names (#18152)

* Clean up query expressions unit tests

* Add tests for StructuredQuery's expression methods

* Append indexes to duplicate expression names

* Fix expression update test

* Test renaming an expression

* Fix handling gaps in expression names with indexes

* Handle duplicate names when updating expressions

* Add issue id to repro test

Co-authored-by: Nemanja Glumac <31325167+nemanjaglumac@users.noreply.github.com>

* Add E2E helper to select notebook steps

* Simplify Cypress test

* [ci nocache]

Co-authored-by: Nemanja Glumac <31325167+nemanjaglumac@users.noreply.github.com>