This is to support model path like :
projects/265104255505/locations/us-central1/publishers/google/models/gemini-2.0-flash-001"
PiperOrigin-RevId: 783413351
set environment variable ADK_ALLOW_WIP_FEATURES=true can bypass it.
working_in_progress features are not working. ADK users are not supposed to set this environment variable.
PiperOrigin-RevId: 771333335