perf(backend): Improve performance of FetchInstanceMetadata (#11128)

* Perf: Avoid retries to acquire lock in fetchInstanceMetadata

* Fix

* Add Changelog

* Fix typo

* Fix lint

* 記法をMisskey式にする

* ????

* refactor
https://github.com/misskey-dev/misskey/pull/11128#pullrequestreview-1518059366



* refactor

* getいらない？

* fix

* fix

* Update CHANGELOG.md

* clean up

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Co-authored-by: tamaina <tamaina@hotmail.co.jp>