fix(grpc): fix segfault with grpc.aio streaming responses

[wconti27]

This PR fixes a few issues with the grpc aio integration. Most notably, the integration was causing segfaults when wrapping async stream responses, most likely since these spans were never being finished. This issue was uncovered when customers upgraded their google-api-core dependencies to 2.17.0; with this upgrade, the package changed many grpc calls to use async streaming. In addition to fixing the segfault, this PR also fixes the Pin object to be correctly placed on the grpcio module.

Fixes #9139

Checklist

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

Reviewer Checklist

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

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: conti/fix-grpc-pin
Commit report: 556d80a
Test service: dd-trace-py

✅ 0 Failed, 447 Passed, 439 Skipped, 4m 11.68s Total duration (1m 11.41s time saved)

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-05-15 18:03:47

Comparing candidate commit 556d80a in PR branch conti/fix-grpc-pin with baseline commit 1cb3487 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 209 metrics, 9 unstable metrics.

[majorgreys]

We should expand on the problem in the PR description so we have context later on about the solution.

[github-actions]

The backport to 1.20 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-1.20 1.20
# Navigate to the new working tree
cd .worktrees/backport-1.20
# Create a new branch
git switch --create backport-9233-to-1.20
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 5897cabe7651f30b0f865ed211c84e1316b49628
# Push it to GitHub
git push --set-upstream origin backport-9233-to-1.20
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-1.20

Then, create a pull request where the base branch is 1.20 and the compare/head branch is backport-9233-to-1.20.