docs: Simplify PR templates

[yinggeh]

What does the PR do?

Internal: remove CI Pipeline ID and commit type sections. Optional GitHub issue. External: remove commit type section.

Checklist

• [x] PR title reflects the change and is of format <commit_type>: <Title>
• [x] Changes are described in the pull request.
• [x] Related issues are referenced.
• [x] Populated github labels field
• [ ] Added test plan and verified test passes.
• [ ] Verified that the PR passes existing CI.
• [x] Verified copyright is correct on all changed files.
• [ ] Added succinct git squash message before merging ref.
• [ ] All template sections are filled out.
• [ ] Optional: Additional screenshots for behavior/output changes with before/after.

Commit Type:

Check the conventional commit type box here and add the label to the github PR.

• [x] docs

Related PRs:

Where should the reviewer start?

Test plan:

• CI Pipeline ID:

Caveats:

Background

Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)

• closes GitHub issue: #xxx