test(flink_application_version): fix incorrect sql

[Serpentiel]

Merging strategy

• [x] Merge
• [ ] Squash

About this change—what it does

• fixes incorrect sql in aiven_flink_application_version resource's test, which resulted the job being in infinite RESTARTING state right after its creation
• fixes heredoc formatting in all docs and tests

Why this way

• sql should be correct in the test to reduce the load the test generates on the service
  • maintainers should later decide whether this is incorrect to report success on creation of such job or not
• heredoc formatting was broken