Replaced other test ids in Buttons

[luixxiul]

Also: modified classNames with cx.

Closes #8090

Auditors:

Test Plan:

1. Open the browser
2. Check for update
3. Make sure the buttons work

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Test Plan:

[NejcZdovc]

LGTM