deps: Update Protobuf-Java to v4.33.6

Author: lqiu96

sdk-platform-java/gapic-generator-java-pom-parent/pom.xml

@@ -31,7 +31,7 @@
     <google.http-client.version>2.2.0</google.http-client.version>
     <gson.version>2.13.2</gson.version>
     <guava.version>33.5.0-jre</guava.version>
-    <protobuf.version>4.33.2</protobuf.version>
+    <protobuf.version>4.33.6</protobuf.version>
     <opentelemetry.version>1.62.0</opentelemetry.version>
     <errorprone.version>2.48.0</errorprone.version>
     <jspecify.version>1.0.0</jspecify.version>