chore: Update protobuf minimum version to 4.x

PiperOrigin-RevId: 650434496

Author: happy-qiao

setup.py

@@ -247,7 +247,7 @@
         ),
         "google-auth >= 2.14.1, <3.0.0dev",
         "proto-plus >= 1.22.0, <2.0.0dev",
-        "protobuf>=3.19.5,<5.0.0dev,!=3.20.0,!=3.20.1,!=4.21.0,!=4.21.1,!=4.21.2,!=4.21.3,!=4.21.4,!=4.21.5",
+        "protobuf>=4.25.3,<5.0.0dev",
         "packaging >= 14.3",
         "google-cloud-storage >= 1.32.0, < 3.0.0dev",
         "google-cloud-bigquery >= 1.15.0, < 4.0.0dev, !=3.20.0",