Fix CI by using client.persist(collection) instead of collection.persist()

[hendrikmakait]

CI has been pretty broken ever since we merged dask/dask#11790.

This PR fixes that.

• Tests added / passed
• Passes pre-commit run --all-files

[jacobtomlinson]

Am I right in understaning that this is because collection.persist() no longer works with an async client?

[hendrikmakait]

Am I right in understaning that this is because collection.persist() no longer works with an async client?

Yes, this raises by default. There is a fallback option but that also warns, so I opted for the explicit usage of the async client.

[hendrikmakait]

get_scheduler() never returns an async client now, so this test has become obsolete.

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

    27 files  ± 0      27 suites  ±0   11h 37m 34s ⏱️ + 15m 0s
 4 100 tests  -  1   3 988 ✅ + 76    111 💤 ±0  1 ❌  -  76 
51 404 runs   - 14  49 107 ✅ +799  2 296 💤  - 1  1 ❌  - 811 

For more details on these failures, see this check.

Results for commit 755b9ea. ± Comparison against base commit ad6f7d9.

This pull request removes 1 test.

distributed.tests.test_client ‑ test_get_scheduler_default_client_config_interleaving

[jacobtomlinson]

Looks good thanks for resolving this @hendrikmakait.

CI failures appear unrelated.