fix(providers): use await request.aread() in OCI async_auth_flow

The async_auth_flow fallback used the sync request.read() method.
Use await request.aread() to stay non-blocking in the async path.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Sébastien Han <seb@redhat.com>

Author: leseb

src/ogx/providers/remote/inference/oci/auth.py

@@ -61,7 +61,7 @@ async def async_auth_flow(self, request: httpx.Request) -> AsyncGenerator[httpx.
         try:
             content = request.content
         except httpx.RequestNotRead:
-            content = request.read()
+            content = await request.aread()
 
         def _sign(content: bytes) -> dict:
             req = requests.Request(