Verify failure of `PipelineRun` in `TestGitPipelineRunFail`
Verify failure of `PipelineRun` in `TestGitPipelineRunFail`

`TestGitPipelineRunFail` is test that is meant to verify that code
extraction fails with invalid inputs to the `Git` `PipelineResource`.

However, the test does not fail if the `PipelineRun` does not succeed.

In this change, we ensure that the `PipelineRun` fails in these
circumstances.

tektoncd/pipeline,tektoncd/pipeline