More fixes of gocritic/govet/testifyrequire

[tstirrat15]

Part of parting out #2455.

Description

The next chunk of changes.

Changes

See commit messages

Testing

Review. See that tests pass.

[codecov]

Codecov Report

❌ Patch coverage is 73.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.71%. Comparing base (048e40c) to head (a6d12b9).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/datastore/memdb/memdb.go	75.00%	3 Missing ⚠️
internal/datastore/postgres/xid8.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2625      +/-   ##
==========================================
- Coverage   77.74%   77.71%   -0.02%     
==========================================
  Files         445      445              
  Lines       55740    55740              
==========================================
- Hits        43328    43314      -14     
- Misses       9717     9727      +10     
- Partials     2695     2699       +4     

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