build(java): skip javadoc tests during dependencies test (#1034)

Author: chingor13

synthtool/gcp/templates/java_library/.kokoro/dependencies.sh

@@ -33,6 +33,7 @@ export MAVEN_OPTS="-Xmx1024m -XX:MaxPermSize=128m"
 retry_with_backoff 3 10 \
   mvn install -B -V -ntp \
     -DskipTests=true \
+    -Dmaven.javadoc.skip=true \
     -Dclirr.skip=true
 
 mvn -B dependency:analyze -DfailOnWarning=true