Disconnect gRPC client stub when shutting down OTLPSpanExporter

[xmakro]

Otherwise the gRPC client will stay connected past the shutdown

Fixes #4429

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: xmakro / name: Makro (9d4e316, 05b0ad7, 0322bf7, 361966c, f90d38f, 3881da6)
• ✅ login: emdneto / name: Emídio Neto (1234b93, 6043a53)
• ✅ login: rjduffner / name: RJ Duffner (a80d72a)
• ✅ login: xrmx / name: Riccardo Magliocchetti (d71bd27, 439defc)

[xrmx]

@xmakro Thanks for the PR, please add a CHANGELOG entry. Can this be tested?

[xmakro]

I added the change log. I don't see a good way to test the disconnect, since it is the gRPC channel that gets disconnected, but these channels are not exposed on the gRPC server side api.

[rjduffner]

@xmakro, do you have time to look into these failures? Or do you mind if I branch and take a stab?

[xmakro]

The checks report a ruff error. I synced this branch to head, updated ruff and ran the pre-commit and cannot reproduce this error. I'm happy if you can fix this by branching.

% git pull
remote: Enumerating objects: 3, done.
remote: Counting objects: 100% (3/3), done.
remote: Compressing objects: 100% (3/3), done.
remote: Total 3 (delta 0), reused 2 (delta 0), pack-reused 0 (from 0)
Unpacking objects: 100% (3/3), 22.66 KiB | 429.00 KiB/s, done.
From https://github.com/xmakro/opentelemetry-python
   d71bd270..f90d38fd  patch-1    -> origin/patch-1
Already up to date.

% pre-commit run --color=always --all-files
ruff.....................................................................Passed
ruff-format..............................................................Passed

[rjduffner]

@xmakro, I was able to reproduce what the linter here was failing on.

xmakro#1

Maybe your ruff settings are set a bit different?

[rjduffner]

@xmakro just checking in here. Does the PR I sent to your fork make sense. Thanks!

[xmakro]

Looks great, thanks! I merged your PR

[rjduffner]

Nice thank you! @xmakro