test(NODE-7534): add prose tests for retry behavior with mixed overload/non-overload errors

[nbbeeken]

Description

Summary of Changes

• Add 4 new prose tests per spec commit 7039e69
• Test 4 (reads/writes): Verify MAX_RETRIES applies to all errors after overload
• Test 5 (reads/writes): Verify backoff only applies to overload errors
• Uses mocking pattern consistent with existing prose tests

Notes for Reviewers

WIP

What is the motivation for this change?

Coverage reccomended by spec

Double check the following

• Lint is passing (npm run check:lint)
• Self-review completed using the steps outlined here
• PR title follows the correct format: type(NODE-xxxx)[!]: description
  • Example: feat(NODE-1234)!: rewriting everything in coffeescript
• Changes are covered by tests
• New TODOs have a related JIRA ticket

[Copilot]

Pull request overview

Adds new prose integration tests to validate the driver’s retry behavior when encountering an initial SystemOverloadedError followed by subsequent non-overload retryable errors, per the referenced spec guidance.

Changes:

• Add new retryable-writes prose cases to verify MAX_RETRIES is honored across mixed overload/non-overload retryable write errors.
• Add new retryable-reads prose cases to verify MAX_RETRIES is honored across mixed overload/non-overload retryable read errors.
• Add timing-based assertions (via measureDuration) to ensure backoff is only applied to overload-labeled errors.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
test/integration/retryable-writes/retryable_writes.spec.prose.test.ts	Adds Case 4/5 prose tests for mixed overload/non-overload retry behavior and backoff timing for retryable writes.
test/integration/retryable-reads/retryable_reads.spec.prose.test.ts	Adds new prose suites to validate max-retry behavior and backoff timing for retryable reads under mixed error-label sequences.