chore: add more info to wsgi read hangs corner cases

[juanjux]

Description

• Add more info to the "skip" of the tests for the wsgi read hangs corner cases.
• Add an actual read on the app.py endpoint to it can be checked that it hangs with or without ddtrace.

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] Risk is outlined (performance impact, potential for breakage, maintainability, etc).
• [X] Change is maintainable (easy to change, telemetry, documentation).
• [X] Library release note guidelines are followed. If no release note is required, add label changelog/no-changelog.
• [X] Documentation is included (in-code, generated user docs, public corp docs).
• [X] Backport labels are set (if applicable)

Reviewer Checklist

• [x] Title is accurate.
• [x] No unnecessary changes are introduced.
• [x] Description motivates each change.
• [x] Avoids breaking API changes unless absolutely necessary.
• [x] Testing strategy adequately addresses listed risk(s).
• [x] Change is maintainable (easy to change, telemetry, documentation).
• [x] Release note makes sense to a user of the library.
• [x] Reviewer has explicitly 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
• [x] If this PR touches code that signs or publishes builds or packages, or handles credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.
• [x] This PR doesn't touch any of that.

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2023-12-12 09:26:19

Comparing candidate commit 820f90b6f31502c33850b433b67ae36f5fe47dff in PR branch juanjux/corner-cases-more-info with baseline commit aa32be7a6d17917199a7da041bb86f62310c7971 in branch main.

Found 1 performance improvements and 2 performance regressions! Performance is the same for 174 metrics, 9 unstable metrics.

scenario:httppropagationextract-all_styles_all_headers

• 🟩 max_rss_usage [-846.058KB; -619.901KB] or [-2.902%; -2.126%]

scenario:httppropagationextract-wsgi_large_valid_headers_all

• 🟥 max_rss_usage [+730.975KB; +940.193KB] or [+2.575%; +3.312%]

scenario:httppropagationextract-wsgi_medium_valid_headers_all

• 🟥 max_rss_usage [+669.238KB; +879.050KB] or [+2.354%; +3.091%]