connpool: Fix handling of expired contexts

[arthurschreiber]

Description

When a context expires, the function that received the context should either return the cause of the expiration (via context.Cause) or wrap the cause of the expiration with a different error (to enrich the error information).

*ConnPool[C].Get did not follow these guidelines. If it was called with an expired context, it would return ErrCtxTimeout instead of the cause of the context expiration, and if the context expired while waiting for a connection, it would return ErrTimeout.

Related Issue(s)

N/A

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.50%. Comparing base (484183c) to head (b6fcb23).
⚠️ Report is 138 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18728      +/-   ##
==========================================
- Coverage   67.50%   67.50%   -0.01%     
==========================================
  Files        1606     1605       -1     
  Lines      263773   263753      -20     
==========================================
- Hits       178048   178034      -14     
+ Misses      85725    85719       -6     

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[github-actions]

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[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

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• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.