Clean up legacy workspace event and metrics

MR: Draft: Clean up legacy workspace events and met... (!198826 - closed)

Description

Workspace already have one internal event and some metrics (using this event) for workspace creation and update GraphQL being called.

These were introduced by this MR.

After we have proper new events and metrics setup, then we should be able to remove the legacy event in the end.

Acceptance criteria

• Remove legacy events users_updating_workspaces, and users_creating_workspaces
• Remove related metrics introduced with above events, see MR here for more details (Moved to use the new dashboard in tableau, so no need to clean up there.)

Implementation plan

NA