Add step that generate issues based on JUnit test results

[ArthurSens]

Description

Now that we're uploading files correctly (#38236), this PR extends the current unit test workflow to download the artifacts and calling issuegenerator to create the issues.

Link to tracking issue

Related to #36761

[ArthurSens]

Weird, I don't even see the issuegenerator logs here 🤔

https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/13596863176/job/38016799607?pr=38270

[ArthurSens]

@mx-psi, I just wanted to let you know that I believe I'll need to patch issuegenerator to make this work.

As seen in this workflow run, issuegenerator is failing with this error:

2025-03-11T22:06:17.144Z	FATAL	issuegenerator@v0.20.0/main.go:244	Failed to search GitHub Issues	{"error": "GET https://api.github.com/repos/open-telemetry/open-telemetry/opentelemetry-collector-contrib/issues?state=open: 404 Not Found []"}

It is writing open-telemetry twice in the URL. See the difference by clicking:

• https://api.github.com/repos/open-telemetry/open-telemetry/opentelemetry-collector-contrib/issues?state=open:
• https://api.github.com/repos/open-telemetry/opentelemetry-collector-contrib/issues?state=open:

The reason behind this is that the ENV variable GITHUB_REPOSITORY doesn't return only the repository but a string like <owner>/<repository>, as shown in the docs.

Issuegenerator is building this API call by concatenating the ENV variables, GITHUB_REPOSITORY_OWNER and GITHUB_REPOSITORY, and since the latter already contains the owners, we're duplicating that information. See code references [1], [2] and [3].

[ArthurSens]

Opened open-telemetry/opentelemetry-go-build-tools#719 to address the problem