Fixes#31697 flaky TestCacheEviction test.
Seen here:
https://github.com/fleetdm/fleet/actions/runs/16802837212/job/47588005349
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## Summary by CodeRabbit
* **Bug Fixes**
* Improved cache stability by adding safety checks to prevent invalid
updates when cache entries are evicted or removed.
* Enhanced eviction logic to prevent out-of-bounds errors during cache
management.
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I noticed a spelling issue and a grammar issue and fixed similar ones
elsewhere in our docs
# Checklist for submitter
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