Fix code coverage file path in CI workflow

[Copilot]

CI workflow failing at code coverage step due to path mismatch.

The dotnet test command uses --results-directory coverage combined with --coverage-output coverage.cobertura.xml. The coverage output path is relative to the results directory, producing coverage/coverage/coverage.cobertura.xml, but the CodeCoverageSummary action was looking for coverage/coverage.cobertura.xml.

Changes

• Updated filename parameter in .github/workflows/build.yaml from coverage/coverage.cobertura.xml to coverage/coverage/coverage.cobertura.xml

Reference: https://github.com/exceptionless/Exceptionless/actions/runs/21479985333/job/61873539380

Original prompt

Reference: https://github.com/exceptionless/Exceptionless/actions/runs/21479985333/job/61873539380

Figure out the RCA for this failure

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