[CI] New upgrade-flavor test group for TestStandaloneUpgrade_Flavor tests

[pazone]

What does this PR do?

Moves upgrade_standalone_flavors_test.go test to the new upgrade-flavor test group.
Added upgrade-flavor group to

• Windows
• Ubuntu x86
• Ubuntu ARM

Why is it important?

upgrade_standalone_flavors_test.go tests take 30 minutes to complete and increase the overall test execution to 1 hour.

Checklist

• I have read and understood the pull request guidelines of this project.
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

How to test this PR locally

Related issues

• Closes https://github.com/elastic/ingest-dev/issues/5061

Questions to ask yourself

• How are we going to support this in production?
• How are we going to measure its adoption?
• How are we going to debug this?
• What are the metrics I should take care of?
• ...

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

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

See analysis details on SonarQube