Python: Agent and Function middleware (#770)

* Initial middleware implementation

* Small fixes

* Small updates

* Small updates in samples

* Moved middleware functionality to decorator

* Removed obsolete file

* Renamed AgentInvocationContext to AzureRunContext

* Added unit tests

* Small settings update for test discovery in VS Code

* Added unit tests

* Reverted changes in environment settings

* Added context result override

* Renaming and updates to logic

* Added more samples

* Updated DEV_SETUP.md

* Addressed PR feedback

* Addressed PR feedback

* Removed unused parameter

* Small fix

* Small fix in telemetry logic

* Revert "Small fix in telemetry logic"

This reverts commit 6f82660d2d.

* Small fix

---------

Co-authored-by: Chris <66376200+crickman@users.noreply.github.com>

python/packages/main/agent_framework/telemetry.py

@@ -1026,8 +1026,12 @@ def _capture_messages(
 
     prepped = prepare_messages(messages)
     for index, message in enumerate(prepped):
+        try:
+            message_data = message.model_dump(exclude_none=True)
+        except Exception:
+            message_data = {"role": message.role.value, "contents": message.contents}
         logger.info(
-            message.model_dump_json(exclude_none=True),
+            message_data,
             extra={
                 OtelAttr.EVENT_NAME: OtelAttr.CHOICE if output else ROLE_EVENT_MAP.get(message.role.value),
                 OtelAttr.PROVIDER_NAME: provider_name,