Drop setuptools from distributed recipe

[jakirkham]

Propagates the dropping of setuptools as a runtime dependency as was done in PR ( #5923 ). Same as the change in the conda-forge recipe ( conda-forge/distributed-feedstock#200 ).

• Closes Drop setuptools runtime dependency? #5949
• Tests added / passed
• Passes pre-commit run --all-files

[jakirkham]

As this only effects the Conda package and that job has passed, going to go ahead and merge.

[github-actions]

Unit Test Results

       12 files  ±0         12 suites  ±0   7h 38m 39s ⏱️ + 1m 17s
  2 665 tests ±0    2 584 ✔️ +4    80 💤 ±0  1 ❌  - 3 
15 902 runs  ±0  15 043 ✔️ +8  858 💤  - 3  1 ❌  - 4 

For more details on these failures, see this check.

Results for commit 8359840. ± Comparison against base commit a5533c0.