chore: switch from surefire to failsafe for integration tests

[orpiske]

Summary

• Replace maven-surefire-plugin with maven-failsafe-plugin so integration tests run during the integration-test/verify lifecycle phases instead of the test phase
• Failsafe's default includes already match the *ITCase.java naming convention, so explicit include patterns are no longer needed
• The test-common module's unit test (TargetConfigurationTest) continues to run under surefire defaults

Test plan

• Run mvn verify and confirm all *ITCase tests execute during the integration-test phase
• Confirm test-common unit test still runs during the test phase

[orpiske]

FYI @lnearlol ... failsafe has better behavior for the integration tests than surefire (that's what it was designed for)