Revert "MINOR: Bump com.google.protobuf:protobuf-bom from 3.25.5 to 4.30.0 (apache#666)"

This reverts commit d13f0e0.

Author: lriggs

flight/flight-core/src/main/java/org/apache/arrow/flight/auth/ClientAuthWrapper.java

@@ -76,7 +76,9 @@ public AuthObserver() {
     @Override
     public void onNext(HandshakeResponse value) {
       ByteString payload = value.getPayload();
-      messages.add(payload.toByteArray());
+      if (payload != null) {
+        messages.add(payload.toByteArray());
+      }
     }
 
     private Iterator<byte[]> iter =

flight/flight-core/src/main/java/org/apache/arrow/flight/auth/ServerAuthWrapper.java

@@ -84,7 +84,9 @@ public AuthObserver(StreamObserver<HandshakeResponse> responseObserver) {
     @Override
     public void onNext(HandshakeRequest value) {
       ByteString payload = value.getPayload();
-      messages.add(payload.toByteArray());
+      if (payload != null) {
+        messages.add(payload.toByteArray());
+      }
     }
 
     private Iterator<byte[]> iter =

flight/flight-integration-tests/src/shade/LICENSE.txt

@@ -272,11 +272,11 @@ License: https://www.apache.org/licenses/LICENSE-2.0
 
 --------------------------------------------------------------------------------
 
-This binary artifact contains Google Protobuf 4.30.2.
+This binary artifact contains Google Protobuf 3.25.5.
 
 Copyright: Copyright 2008 Google Inc.  All rights reserved.
 Home page: https://protobuf.dev/
-License: https://github.com/protocolbuffers/protobuf/blob/v4.30.1/LICENSE (BSD)
+License: https://github.com/protocolbuffers/protobuf/blob/v3.25.5/LICENSE (BSD)
 License text:
 
 | Copyright 2008 Google Inc.  All rights reserved.

flight/flight-sql-jdbc-driver/src/shade/LICENSE.txt

@@ -234,11 +234,11 @@ License: https://www.apache.org/licenses/LICENSE-2.0
 
 --------------------------------------------------------------------------------
 
-This binary artifact contains Protobuf 4.30.2.
+This binary artifact contains Protobuf 3.25.5.
 
 Copyright: Copyright 2008 Google Inc.  All rights reserved.
 Home page: https://protobuf.dev/
-License: https://github.com/protocolbuffers/protobuf/blob/v4.30.1/LICENSE (BSD)
+License: https://github.com/protocolbuffers/protobuf/blob/v3.25.3/LICENSE (BSD)
 License text:
 
 | Copyright 2008 Google Inc.  All rights reserved.

pom.xml

@@ -100,7 +100,7 @@ under the License.
     <dep.guava-bom.version>33.4.8-jre</dep.guava-bom.version>
     <dep.netty-bom.version>4.2.9.Final</dep.netty-bom.version>
     <dep.grpc-bom.version>1.79.0</dep.grpc-bom.version>
-    <dep.protobuf-bom.version>4.33.4</dep.protobuf-bom.version>
+    <dep.protobuf-bom.version>3.25.5</dep.protobuf-bom.version>
     <dep.jackson-bom.version>2.21.0</dep.jackson-bom.version>
     <dep.hadoop.version>3.4.3</dep.hadoop.version>
     <dep.fbs.version>25.2.10</dep.fbs.version>