chore: re-add message size limits

Author: olavloite

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpc.java

@@ -344,6 +344,8 @@ public GapicSpannerRpc(final SpannerOptions options) {
           InstantiatingGrpcChannelProvider.newBuilder()
               .setChannelConfigurator(options.getChannelConfigurator())
               .setEndpoint(options.getEndpoint())
+              .setMaxInboundMessageSize(MAX_MESSAGE_SIZE)
+              .setMaxInboundMetadataSize(MAX_METADATA_SIZE)
               .setPoolSize(options.getNumChannels())
 
               // Set a keepalive time of 120 seconds to help long running