Fix contributions calendar month label truncation

What does this MR do?

Expands the width of the contributions calendar by 3px when the last column is a new month to prevent the month label from being truncated

Are there points in the code the reviewer needs to double check?

Shouldn't be

Why was this MR needed?

Fixes an existing UI issue

What are the relevant issue numbers?

Closes #20844 (closed)

Screenshots (if relevant)

Before:

After:

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Tests
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together

@connorshea can you review this please?

Added ~164274 frontend labels

@smcgivern can you take a look please?

This looks good to me, @ClemMakesApps! @annabeldunstone, could you take a look please?

Resolved all discussions

Added 1 commit:

• f71a94ad - Fix contributions calendar month label truncation

Added 1060 commits:

• f71a94ad...f66a6b31 - 1059 commits from branch gitlab-org:master
• d7a3aa74 - Fix contributions calendar month label truncation

@alfredo1 is probably a better person to review this

Reassigned to @alfredo1

Added 37 commits:

• d7a3aa74...9b079219 - 36 commits from branch gitlab-org:master
• 4f88e683 - Fix contributions calendar month label truncation

Added 24 commits:

• 4f88e683...02591b04 - 23 commits from branch gitlab-org:master
• 524931dc - Fix contributions calendar month label truncation

Added 26 commits:

• 524931dc...cd6157d5 - 25 commits from branch gitlab-org:master
• ac31e857 - Fix contributions calendar month label truncation

Added 26 commits:

• ac31e857...a03da79f - 25 commits from branch gitlab-org:master
• 4315c04d - Fix contributions calendar month label truncation

Added 9 commits:

• 4315c04d...b099a10e - 8 commits from branch gitlab-org:master
• 72d7ae1a - Fix contributions calendar month label truncation

I think @iamphill will be better reviewing this since he's familiar with the code.

Reassigned to @iamphill

Added 87 commits:

• 72d7ae1a...501b570d - 86 commits from branch gitlab-org:master
• 7527f868 - Fix contributions calendar month label truncation

Added 11 commits:

• 7527f868...1bf2fe27 - 10 commits from branch gitlab-org:master
• 9da9c4c1 - Fix contributions calendar month label truncation