Add compiled dangerfile.js to .gitignore and .eslintignore

[gerteck]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• Feature addition or enhancement
• Code maintenance
• DevOps
• Improve developer experience
• Others, please explain:

Overview of changes:

Fixes #2595

Compiled js file after running npm run setup or npm run build:backend which compiles ts files into js files through tsc --noEmitOnError not listed to be ignored by git, cuasing some inconvenience especially during development.

Added the compiled js file into both gitignore and eslint ignore.

Anything you'd like to highlight/discuss:

Testing instructions:

Proposed commit message: (wrap lines at 72 characters)

Update gitignore and eslintignore

Added dangerfile.js compiled from tsc to respective ignores.

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Checklist: ☑️

• Updated the documentation for feature additions and enhancements
• Added tests for bug fixes or features
• Linked all related issues
• No unrelated changes

---

Reviewer checklist:

Indicate the SEMVER impact of the PR:

• Major (when you make incompatible API changes)
• Minor (when you add functionality in a backward compatible manner)
• Patch (when you make backward compatible bug fixes)

At the end of the review, please label the PR with the appropriate label: r.Major, r.Minor, r.Patch.

Breaking change release note preparation (if applicable):

• To be included in the release note for any feature that is made obsolete/breaking

Give a brief explanation note about:

• what was the old feature that was made obsolete
• any replacement feature (if any), and
• how the author should modify his website to migrate from the old feature to the replacement feature (if possible).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.86%. Comparing base (4ed8781) to head (b29722b).
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2601   +/-   ##
=======================================
  Coverage   51.86%   51.86%           
=======================================
  Files         127      127           
  Lines        5474     5474           
  Branches     1201     1201           
=======================================
  Hits         2839     2839           
  Misses       2340     2340           
  Partials      295      295           

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[lhw-1]

Just to provide more context: Dangerfile.ts was added in #2523 to address #2140. This PR is mainly to fix a small bug arising from Dangerfile.ts needlessly being compiled into .js.

(If there is some missing context, i.e. if this was not an oversight but was intended, feel free to comment further)

[lhw-1]

LGTM! This should make development less annoying for all.

[github-actions]

@lhw-1 Each PR must have a SEMVER impact label, please remember to label the PR properly.