fix: Fix PrivateEndpoint.raw_predict parameter name

[yashwantbezawada]

Fixes #6101

Description

Fixed TypeError in PrivateEndpoint.raw_predict() caused by incorrect parameter name when calling AuthorizedSession.post().

Problem

When calling PrivateEndpoint.raw_predict() with PSC (Private Service Connect) based endpoints, the method crashed with:

TypeError: Session.request() got an unexpected keyword argument 'body'

Root Cause

The google-auth-transport library updated its API, changing the parameter name from body to data for AuthorizedSession.post().

The Endpoint.raw_predict() method was updated to use data, but PrivateEndpoint.raw_predict() was missed and still used body.

Changes

File: google/cloud/aiplatform/models.py
Line: 4153

Changed:

return self._authorized_session.post(
    url=url,
    body=body,  # ← incorrect parameter name
    headers=headers,
)

To:

return self._authorized_session.post(
    url=url,
    data=body,  # ← correct parameter name
    headers=headers,
)

Testing

This fix aligns PrivateEndpoint.raw_predict() with the already-corrected Endpoint.raw_predict() implementation (line 2744), which uses data=body.

The issue reporter confirmed the fix resolves the crash when calling raw_predict() on PSC-based PrivateEndpoint instances.

[matthew29tang]

Merged as 3d380ba