fix: Adding detailed information on each metric evaluation

Additionally, few other small changes.
*   Updated a test fixture to support the latest eval data schema. Somehow I missed doing that previously.
*   Updated the `evaluation_generator.py` to use `run_async`, instead of `run`.
*   Also, raise an informed error when dependencies required eval are not installed.
*   Also, changed the behavior of AgentEvaluator.evaluate method to run all the evals, instead of failing at the first eval metric failure.

PiperOrigin-RevId: 775919127

src/google/adk/evaluation/evaluation_generator.py

@@ -182,7 +182,7 @@ class EvaluationGenerator:
       tool_uses = []
       invocation_id = ""
 
-      for event in runner.run(
+      async for event in runner.run_async(
           user_id=user_id, session_id=session_id, new_message=user_content
       ):
         invocation_id = (