Python: fix(google_ai): report more Gemini finish reasons as content_filter (#14632)

### Motivation and Context

`finish_reason_from_google_ai_to_semantic_kernel` only mapped `SAFETY`
to `FinishReason.CONTENT_FILTER`. Gemini also ends a response for
`RECITATION`, `BLOCKLIST`, `PROHIBITED_CONTENT` and `SPII` (and the
image variants available across the supported google-genai range), and
for those the message came back with `finish_reason=None`,
indistinguishable from an unrecognised value or an unfinished response.

### Description

- `SAFETY`, `RECITATION`, `BLOCKLIST`, `PROHIBITED_CONTENT`, `SPII`,
`IMAGE_SAFETY` and `IMAGE_PROHIBITED_CONTENT` map to
`FinishReason.CONTENT_FILTER`.
- `STOP` and `MAX_TOKENS` are unchanged; other reasons (`OTHER`,
`MALFORMED_FUNCTION_CALL`, ...) still return `None`.
- A parametrized unit test covers the new reasons; its 6 cases fail on
`main` and pass with the change. `tests/unit/connectors/ai/google`
passes (158).
- The deprecated `vertex_ai` connector is left as is.

### Contribution Checklist

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the SK Contribution Guidelines
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

This change was made with Claude Code; the tests were run against `main`
and the branch.

Author: pcbeingused333

python/semantic_kernel/connectors/ai/google/google_ai/services/utils.py

@@ -31,6 +31,18 @@
 logger: logging.Logger = logging.getLogger(__name__)
 
 
+# Finish reasons where Gemini stopped the response for the content, not for length or a natural end.
+_GOOGLE_AI_CONTENT_FILTER_REASONS = frozenset({
+    FinishReason.SAFETY,
+    FinishReason.RECITATION,
+    FinishReason.BLOCKLIST,
+    FinishReason.PROHIBITED_CONTENT,
+    FinishReason.SPII,
+    FinishReason.IMAGE_SAFETY,
+    FinishReason.IMAGE_PROHIBITED_CONTENT,
+})
+
+
 def finish_reason_from_google_ai_to_semantic_kernel(
     finish_reason: FinishReason | None,
 ) -> SemanticKernelFinishReason | None:
@@ -47,7 +59,7 @@ def finish_reason_from_google_ai_to_semantic_kernel(
     if finish_reason == FinishReason.MAX_TOKENS:
         return SemanticKernelFinishReason.LENGTH
 
-    if finish_reason == FinishReason.SAFETY:
+    if finish_reason in _GOOGLE_AI_CONTENT_FILTER_REASONS:
         return SemanticKernelFinishReason.CONTENT_FILTER
 
     return None

python/tests/unit/connectors/ai/google/google_ai/services/test_google_ai_utils.py

@@ -33,6 +33,22 @@ def test_finish_reason_from_google_ai_to_semantic_kernel():
     assert finish_reason_from_google_ai_to_semantic_kernel(None) is None
 
 
+@pytest.mark.parametrize(
+    "reason",
+    [
+        FinishReason.RECITATION,
+        FinishReason.BLOCKLIST,
+        FinishReason.PROHIBITED_CONTENT,
+        FinishReason.SPII,
+        FinishReason.IMAGE_SAFETY,
+        FinishReason.IMAGE_PROHIBITED_CONTENT,
+    ],
+)
+def test_content_filter_finish_reasons_from_google_ai(reason):
+    """Responses Gemini stopped for their content are reported as content filtered."""
+    assert finish_reason_from_google_ai_to_semantic_kernel(reason) == SemanticKernelFinishReason.CONTENT_FILTER
+
+
 def test_format_user_message():
     """Test format_user_message."""
     user_message = ChatMessageContent(role=AuthorRole.USER, content="User message")