opentelemetry-exporter-otlp-proto-http: Update exporter to use new HTTP transport package

[herin049]

Description

This PR updates the opentelemetry-exporter-otlp-proto-http package to switch to using the abstractions/utilities added in the opentelemetry-exporter-http-transport package. Notably, this involves switching to the shared OTLPHTTPClient client (reducing code duplication between exporters), and adding an optional, private _transport argument that accepts an arbitrary transport implementation. These changes also switch to using urllib3 as the default transport, unless the user specifies otherwise, either by directly passing a requests Session, initializing the _OTEL_PYTHON_EXPORTER_OTLP_HTTP_CREDENTIAL_PROVIDER environment variable or directly passing a custom transport via the _transport keyword argument.

Fixes #3439, #4171, #2990

Depends on #5194

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

uv run tox -e py314-test-opentelemetry-exporter-otlp-proto-http

Does This PR Require a Contrib Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[github-actions]

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[codeboten]

With #5194 merged, can this move forward?

[herin049]

With #5194 merged, can this move forward?

Sorry for the delay, this is still dependent on this PR: #5252 due to the decision to isolate the OTLPHTTPClient into its own package.

Once #5252 is merged, then it will unblock a lot of work. (e.g. finishing the OTLP JSON exporter and generalizing the OTLP HTTP exporter)

[github-actions]

This PR has been automatically marked as stale because it has not had any activity for 14 days. It will be closed if no further activity occurs within 14 days of this comment.
If you're still working on this, please add a comment or push new commits.

[herin049]

superseded by #5389