chore(hubble): Enhance code style in hubble

[returnToInnocence]

Purpose of the PR

• subtask of [Enhancement] Unify & clean code style in hubble & client #591

Main Changes

Verifying these changes

• Trivial rework / code cleanup without any test coverage. (No Need)
• Already covered by existing tests, such as (please modify tests here).
• Need tests and can be verified as follows:
  • Check against the HugeGraph Code Style Guide

Does this PR potentially affect the following parts?

• Nope
• Dependencies (add/update license info)
• Modify configurations
• The public API
• Other affects (typed here)

Documentation Status

• Doc - TODO
• Doc - Done
• Doc - No Need

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 62.41%. Comparing base (b066b80) to head (110cd1e).
Report is 27 commits behind head on master.

❗ Current head 110cd1e differs from pull request most recent head 7bf19b2. Consider uploading reports for the commit 7bf19b2 to get more accurate results

Additional details and impacted files

@@ Coverage Diff @@ ## master #592 +/- ## ============================================ - Coverage 62.49% 62.41% -0.08%  - Complexity 1903 1931 +28  ============================================ Files 262 267 +5 Lines 9541 9739 +198 Branches 886 891 +5 ============================================ + Hits 5963 6079 +116  - Misses 3190 3267 +77  - Partials 388 393 +5 

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[imbajin]

Thanks~