ci: add `importlib_metadata` to `test_get_distributions` [backport 2.7]

[gnufede]

Follow-up on: https://github.com/DataDog/dd-trace-py/pull/9467/files#r1642430035

Checklist

• [x] Change(s) are motivated and described in the PR description
• [x] Testing strategy is described if automated tests are not included in the PR
• [x] Risks are described (performance impact, potential for breakage, maintainability)
• [x] Change is maintainable (easy to change, telemetry, documentation)
• [x] Library release note guidelines are followed or label changelog/no-changelog is set
• [x] Documentation is included (in-code, generated user docs, public corp docs)
• [x] Backport labels are set (if applicable)
• [x] If this PR changes the public interface, I've notified @DataDog/apm-tees.

Reviewer Checklist

• [x] Title is accurate
• [x] All changes are related to the pull request's stated goal
• [x] Description motivates each change
• [x] Avoids breaking API changes
• [x] Testing strategy adequately addresses listed risks
• [x] Change is maintainable (easy to change, telemetry, documentation)
• [x] Release note makes sense to a user of the library
• [x] Author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• [x] Backport labels are set in a manner that is consistent with the release branch maintenance policy

(cherry picked from commit 68bb423a2ed3ef23a87eb34d32ac96c8d1005016)

[datadog-dd-trace-py-rkomorn[bot]]

Datadog Report

Branch report: backport-9562-to-2.7 Commit report: 3f19243 Test service: dd-trace-py

:white_check_mark: 0 Failed, 58567 Passed, 113190 Skipped, 10h 33m 11.38s Total duration (2h 2m 43.65s time saved)

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2024-06-24 09:04:37

Comparing candidate commit 3f192432e8bb43a5e653fb19d692f967d62f96e0 in PR branch backport-9562-to-2.7 with baseline commit ece781c9e8d76d8c2b734654c083c09045187f56 in branch 2.7.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 201 metrics, 9 unstable metrics.