Ensure workers are not downscaled when participating in p2p

[fjetter]

Closes https://github.com/dask/distributed/issues/8579

[github-actions[bot]]

Unit Test Results

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

    29 files  ± 0      29 suites  ±0   10h 57m 36s :stopwatch: - 17m 53s  4 061 tests + 1   3 948 :white_check_mark: + 1    109 :zzz: ±0  4 :x: ±0  54 970 runs  +30  52 557 :white_check_mark: +36  2 409 :zzz:  - 6  4 :x: ±0 

For more details on these failures, see this check.

Results for commit 9b302e7a. ± Comparison against base commit 66ced13b.

:recycle: This comment has been updated with latest results.