Use application list to determine if team is empty (backport #2035)

[github-actions]

Backport of #2035

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Fixes #2031

Description

Uses the application list api to determine if the team is empty or not.

Adds test coverage for the team delete ui.

Note: I've had to add the new _spec file to the list of those for which the require-data-selectors lint rule is disabled. This is because the fix is needed upstream in ui-components to add data attributes to the ff-dialog components.

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
• Upgrade instructions
• Configuration details
• Concepts
• Changes flowforge.yml?
• Issue/PR raised on flowforge/helm to update ConfigMap Template
• Issue/PR raised on flowforge/CloudProject to update values for Staging/Production

Labels

• Backport needed? -> add the backport label
• Includes a DB migration? -> add the area:migration label