Implement red team user agent for RAI service calls

Co-authored-by: slister1001 <[email protected]>

Author: Copilot

sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_user_agent.py

@@ -9,11 +9,13 @@
 
 class UserAgentSingleton:
     __BASE_USER_AGENT: str = "{}/{}".format("azure-ai-evaluation", VERSION)
+    __REDTEAM_USER_AGENT: str = "{}-redteam/{}".format("azure-ai-evaluation", VERSION)
+    __is_redteam_context: bool = False
 
     @property
     def value(self):
         """Get the user-agent"""
-        return self.__BASE_USER_AGENT
+        return self.__REDTEAM_USER_AGENT if self.__is_redteam_context else self.__BASE_USER_AGENT
 
     def __str__(self) -> str:
         return self.value
@@ -35,3 +37,18 @@ def add_useragent_product(cls, *product: str) -> Iterator[None]:
         yield
 
         cls.__BASE_USER_AGENT = old_useragent
+
+    @classmethod
+    @contextmanager
+    def redteam_context(cls) -> Iterator[None]:
+        """Context manager to use red team user agent for RAI service calls
+
+        This context manager temporarily sets the user agent to "azure-ai-evaluation-redteam"
+        for all calls within the context.
+        """
+        old_context = cls.__is_redteam_context
+        cls.__is_redteam_context = True
+
+        yield
+
+        cls.__is_redteam_context = old_context