We convert the following elements to use a class instead of
id for accessing them across the codebase:
* markdown_preview
* undo_markdown_preview
* markdown_preview_spinner
* message_edit_content
* preview_content
Converted them together since changes to one impacted the other in
some modules like click_handlers.
Also, added a function in rows to get `message_row`.
Changed the name of the test-user cordelia from `Cordelia Lear` to
`Cordelia, Lear's daughter`.
This change will enable us to test users with escape characters in
their names.
I also updated the Node, Puppeteer, Backend tests and Fixtures to
support this change.
The only downside of this is that it makes it harder to control the
order of these tests; which isn't that important. And the structure
of naming each with its test order fundamentally requires renaming
files when adding/deleting tests, so if we want to control the default
test order, we'd be better off doing that by just hardcoding a list in
the test runner code.
Aman Agrawal
Arun Sankar
Riken Shah