Refactor naming and usage of Web IDE left-pane related constants
What does this MR do?
This is a refactoring to support a collapsible left sidebar. See the epic for more context: &2585
This work has already been done in !21010 (closed), this is just a more incremental approach.
rename constants from
Change structure of constants to match
Replace all occurrences of
Does this MR meet the acceptance criteria?
Closes #204817 (closed)