chore: collapse conversation sidebar sections (folders, teams, inboxes and labels) - CW-7059 (#14509)

## Description

Added ability to collapse conversation sidebar sections (folders, teams,
inboxes and labels)

Fixes #CW-7059

## Type of change

Please delete options that are not relevant.

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality not to work as expected)
- [ ] This change requires a documentation update

## How Has This Been Tested?

Tested locally. Added specs. Attaching the loom for them same.


https://github.com/user-attachments/assets/40d613e7-6c82-4078-abf4-79739a00f718


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>

app/javascript/dashboard/constants/localStorage.js

@@ -7,4 +7,5 @@ export const LOCAL_STORAGE_KEYS = {
   DISMISSED_LABEL_SUGGESTIONS: 'labelSuggestionsDismissed',
   MESSAGE_REPLY_TO: 'messageReplyTo',
   RECENT_SEARCHES: 'recentSearches',
+  SIDEBAR_MINIMIZED_SECTIONS: 'sidebarMinimizedSections',
 };