ci: skip coverage uploads off default branch

[baywet]

Summary

• only upload GitHub code coverage on pull requests from this repository
• allow branch uploads only on the repository default branch
• skip uploads on other branch push and workflow_dispatch runs to avoid post-merge 400 errors on support/v2

Backport

• cherry-picks 75f3144 from main

[github-code-quality]

Code Coverage Overview

Languages: C#

C# / code-coverage/dotnet

The overall coverage in the ci/coverage-informat... branch is 41%. The coverage in the support/v2 branch is 42%.

Show a code coverage summary of the most impacted files.

File	support/v2 ea95d88	ci/coverage-informat... d36e941	+/-
/home/runner/wo...Deserializer.cs	79%	44%	-35%
/home/runner/wo...Deserializer.cs	97%	66%	-31%
/home/runner/wo...Deserializer.cs	97%	66%	-31%
/home/runner/wo...Deserializer.cs	90%	60%	-30%
/home/runner/wo...penApiServer.cs	97%	71%	-26%
/home/runner/wo...s/OpenApiTag.cs	100%	76%	-24%
/home/runner/wo...Deserializer.cs	100%	83%	-17%
/home/runner/wo...Deserializer.cs	96%	81%	-15%
/home/runner/wo...piComponents.cs	94%	87%	-7%
/home/runner/wo...Deserializer.cs	89%	96%	+7%

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud