kv: spurious ambiguous errors can be returned

**Describe the problem**

The test `kv/gracefuldraining` fails without disabling the max gossip frequency.

Customers expect to not hit ambiguous errors during clean drains and shutdowns. This is a somewhat expected and rare error and we expect customers to retry, but it is still a regression in behavior.

**To Reproduce**

Remove the `--tolerate-errors` line from the test. It will fail ~50% of the time.

**Expected behavior**
Customers expect to not hit ambiguous errors during clean drains and shutdowns. This is a somewhat expected and rare error and we expect customers to retry, but it is still a regression in behavior.

Jira issue: CRDB-41538

Start with the kv/gracefuldraining test and reproduce the failure by removing the --tolerate-errors line while leaving max gossip frequency enabled. Trace the ambiguous errors during clean drains and shutdowns. Done means the test passes without tolerating those errors and clean shutdowns no longer produce the regression.

Written by the indexing model from the issue text.