Bump google-auth 2.48.0 -> 2.53.0

- Dependency update with security patches and bug fixes
- Removes rsa as a transitive dependency (no longer needed)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: rayharnett

pyproject.toml

@@ -58,7 +58,7 @@ dependencies = [
     "fideslang==3.1.3",
     "firebase-admin==5.3.0",
     "flower==2.0.1",
-    "google-auth==2.48.0",
+    "google-auth==2.53.0",
     "httpx~=0.28.1",
     "iab-tcf==0.2.2",
     "immutables==0.21",