refactor: Use custom function to format month instead of date-fns function

[abdhalees]

format function from date-fns added 5kb to our bundle, since this is the only usage of it in our codebase, removing it and formatting month manually saves the 5kb.

Description

Related links, issue #, if available: n/a

How has this been tested?

there is already a unit test for it

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.39%. Comparing base (85cb377) to head (43ff055).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3131   +/-   ##
=======================================
  Coverage   96.39%   96.39%           
=======================================
  Files         784      784           
  Lines       22062    22065    +3     
  Branches     7564     7505   -59     
=======================================
+ Hits        21266    21269    +3     
  Misses        744      744           
  Partials       52       52           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[TrevorBurnham]

@abdhalees You may be interested in this PR, which replaces date-fns with a more lightweight library, dayjs: #3786