Actually skip test failures during SonarCloud analysis

[Stephan202]

Extracted from #603.

Suggested commit message:

Actually skip test failures during SonarCloud analysis (#986)

To test, run:

vimdiff \
  <(mvn help:effective-pom) \
  <(mvn help:effective-pom -Dsonar.projectKey=PicnicSupermarket_error-prone-support)

[github-actions]

Looks good. No mutations were possible for these changes.
Mutation testing report by Pitest. Review any surviving mutants by inspecting the line comments under Files changed.

[sonarqubecloud]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[mohamedsamehsalah]

To test, run:

vimdiff \
  <(mvn help:effective-pom) \
  <(mvn help:effective-pom -Dsonar.projectKey=PicnicSupermarket_error-prone-support)

Don't have experience with vimdiff so not sure what I am supposed to be looking at here 🙈

[Stephan202]

It's not a question of vimdiff; any diff would suffice. It should show that on this branch maven.test.failure.ignore is set only in the latter case. (While without this PR there'd be no diff.)

I do see that I failed to add a backslash to the command; try again :)