fix: cluster.metricsCollector invoked before assign when MountWebhooks(#1428)

[tao12345666333]

Type of change:

• Bugfix
• New feature provided
• Improve performance
• Backport patches

What this PR does / why we need it:

Pre-submission checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (v1.5.0@a288408). Click here to learn what that means.
The diff coverage is n/a.

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