fix(integrations): do not exit early when config is not passed as it is not required and prohibits setting gen_ai.request.messages (#5167)

#### Issues

Closes
https://linear.app/getsentry/issue/TET-1454/py-google-genai-request-messages-missing

Author: constantinius

sentry_sdk/integrations/google_genai/utils.py

@@ -442,19 +442,14 @@ def set_span_data_for_request(span, integration, model, contents, kwargs):
     if kwargs.get("stream", False):
         span.set_data(SPANDATA.GEN_AI_RESPONSE_STREAMING, True)
 
-    config = kwargs.get("config")
-
-    if config is None:
-        return
-
-    config = cast(GenerateContentConfig, config)
+    config = kwargs.get("config")  # type: Optional[GenerateContentConfig]
 
     # Set input messages/prompts if PII is allowed
     if should_send_default_pii() and integration.include_prompts:
         messages = []
 
         # Add system instruction if present
-        if hasattr(config, "system_instruction"):
+        if config and hasattr(config, "system_instruction"):
             system_instruction = config.system_instruction
             if system_instruction:
                 system_text = extract_contents_text(system_instruction)
@@ -496,7 +491,7 @@ def set_span_data_for_request(span, integration, model, contents, kwargs):
                 span.set_data(span_key, value)
 
     # Set tools if available
-    if hasattr(config, "tools"):
+    if config is not None and hasattr(config, "tools"):
         tools = config.tools
         if tools:
             formatted_tools = _format_tools_for_span(tools)