Move frontend handler's client version check to generated code

[Shaddoll]

What changed?

• Move frontend handler version check to generated code
• This also reverse the order of client version check and shutdown check

Why?
To improve code coverage (57 lines)

How did you test it?
Unit tests

Potential risks

Release notes

Documentation Changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.92%. Comparing base (b8f6da5) to head (ee3db84).
Report is 5 commits behind head on master.

Additional details and impacted files

Files with missing lines	Coverage Δ
service/frontend/api/handler.go	64.89% <ø> (+1.17%)	⬆️

... and 10 files with indirect coverage changes

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