refactor(CDN): refactor update domain full config function

[deer-hang]

What this PR does / why we need it:

The existing method of editing the full configuration cannot edit cache_settings alone. In order to solve this problem, the editing logic was adjusted.

Which issue this PR fixes: (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged) fixes #xxx

Special notes for your reviewer:

Release note:

PR Checklist

• [X] Tests added/passed.
• [ ] Documentation updated.
• [ ] Schema updated.

Acceptance Steps Performed

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