Added if check and return error for filters with empty groups fix#38896

[SudeshHirave]

Problem

Closes #38896

Changes

Added if check for empty groups and gave an proper error for for creating a feature flag with empty groups

How did you test this code?

• Bug Fixes
  • Prevents saving feature flag filters with an empty "groups" list; attempts now return a clear validation error.

[greptile-apps]

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

style: The error message string is split across multiple lines without proper indentation. Consider formatting it properly:

Suggested change

	raise serializers.ValidationError(
	"Feature flag filters must contain at least one condition set. Empty 'groups' array is not allowed."
	)
	raise serializers.ValidationError(
	"Feature flag filters must contain at least one condition set. Empty 'groups' array is not allowed."
	)

Prompt To Fix With AI

This is a comment left during a code review.
Path: posthog/api/feature_flag.py
Line: 399:401

Comment:
**style:** The error message string is split across multiple lines without proper indentation. Consider formatting it properly:

```suggestion
            raise serializers.ValidationError(
                "Feature flag filters must contain at least one condition set. Empty 'groups' array is not allowed."
            )
```

How can I resolve this? If you propose a fix, please make it concise.