ci: fix minor release note generation bugs

[jmartin4563]

Description

Now that we've done a full end-to-end test of the new Conventional Commit release process, there are a few final tweeks we wanted to make:

1. Remove newlines added to PR/Commit SHA links in Markdown changelog generation process
2. Moved PR link removal in commit subject from the JSON changelog generation process only to the commit generation process, so both the Markdown and JSON changelog have it removed from the subject.
3. Update Github Release script string processing to gracefully handle multiple types of markdown headings
4. Remove unused Github Action workflow with syntax errors

How to Test

• 1 and 2 are exercised in the unit tests
• 3 can be tested by commenting out Line 64 in create-github-release.js, and running the following

node ./bin/create-github-release.js --tag v10.1.1 --repo newrelic/node-newrelic --changelog NEWS.md

Related Issues

Closes NR-117586

[codecov]

Codecov Report

Merging #1643 (57e2f03) into main (b924534) will increase coverage by 2.88%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1643      +/-   ##
==========================================
+ Coverage   93.67%   96.55%   +2.88%     
==========================================
  Files         181      200      +19     
  Lines       37154    39064    +1910     
  Branches       24       24              
==========================================
+ Hits        34803    37720    +2917     
+ Misses       2351     1344    -1007     

Flag	Coverage Δ
esm-unit-tests-14.x	47.80% <ø> (ø)
esm-unit-tests-16.x	92.11% <ø> (ø)
esm-unit-tests-18.x	92.11% <ø> (ø)
integration-tests-14.x	78.97% <ø> (ø)
integration-tests-16.x	79.06% <ø> (ø)
integration-tests-18.x	79.07% <ø> (ø)
unit-tests-14.x	90.66% <ø> (ø)
unit-tests-16.x	90.72% <ø> (ø)
unit-tests-18.x	90.70% <ø> (ø)
versioned-tests-14.x	75.29% <ø> (?)
versioned-tests-16.x	76.59% <ø> (?)
versioned-tests-18.x	76.59% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

see 44 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more