fix(ci): Labeling doc needed PRs with uppercase checkbox - [X]

[Savio-Sou]

Description

The doc needed labeling CI was able to detect - [x] but not - [X] documentation checkbox on PRs. (See #1271 as an example.)

This PR fixes the labeling CI to label a PR when either a - [x] or - [X] documentation checkbox is detected.

Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt with default settings.
• I have linked this PR to the issue(s) that it resolves.
• I have reviewed the changes on GitHub, line by line.
• I have ensured all changes are covered in the description.

Documentation needs

• This PR requires documentation updates when merged.

Additional context

PR in testing repo for reference: noir-lang-test#9

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chore(ci): allow labeling doc needed PRs with uppercase X
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