refactor JWT parse

[WindzCUHK]

Description

• refactor access token parse logic
• remove checkbox in PR template

Type of change

• [ ] Bug fix
• [ ] New feature
• [x] Refactoring (no functional changes, no api changes)
• [ ] Non-code changes (update documentation, pipeline, etc.)

Flags

• [ ] Breaks backward compatibility
• [ ] Requires a documentation update
• [ ] Has untestable code

Related issue/PR

• 30

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Checklist

• [x] Followed the guidelines in the CONTRIBUTING document
• [x] Added prefix [skip ci]/[ci skip]/[no ci]/[skip actions]/[actions skip] in the PR title if necessary
• [x] Tested and linted the code
• [x] Commented the code
• [x] Made corresponding changes to the documentation
• [ ] Passed all pipeline checking

Checklist for maintainer

• Use Squash and merge
• Double-confirm the merge message has prefix [skip ci]/[ci skip]/[no ci]/[skip actions]/[actions skip]
• Delete the branch after merge