Fix silent Agentspace agent runs when authorization is registered

# Fix silent Agentspace agent runs when authorization is registered

## What's going on

An agent registered in Agentspace (Gemini Enterprise) with authorization failed at call time with a 400 error: "Agent finished execution without providing any response" (AGENT_ENGINE_FAILED_PRECONDITION from discoveryengine.googleapis.com). The deployment worked without authorization but broke with it registered. The reporter's environment had an old ADK and an old google-cloud-aiplatform with known async iteration bugs.

## The verified fix

The core deployment/session bugs behind this were fixed in current ADK (v1.24.0+): ADK now requires `google-cloud-aiplatform>=1.132.0` (past the buggy 1.126.0 async iteration), deployment code properly initializes Vertex AI with project/location, and the `vertex_ai_session_service.py` async event iteration was fixed. Upgrade with `pip install google-adk google-cloud-aiplatform --upgrade`. Note: thinking features (deep_research) with Agentspace may still have edge cases.
Source: https://github.com/google/adk-python/issues/3534

## How to use this

Take the question above and check if it matches what you're seeing. If it does, work through the verified fix step by step. Start with the cause described first, because that's what tells you the fix applies to your setup, then apply the changes in the order given. Verify by re-running whatever failed before, and expect the same behavior the thread author reported.