chore(java-firestore): modernize submodule pom.xml

Author: chingor13

java-firestore/grpc-google-cloud-firestore-admin-v1/pom.xml

@@ -45,26 +45,6 @@
             <artifactId>guava</artifactId>
         </dependency>
     </dependencies>
-    <reporting>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-javadoc-plugin</artifactId>
-                <configuration>
-                    <show>protected</show>
-                    <nohelp>true</nohelp>
-                    <doclint>none</doclint>
-                    <splitindex>true</splitindex>
-                    <offlineLinks>
-                        <offlineLink>
-                            <url>${project.javadoc.protobufBaseURL}</url>
-                            <location>../../../../proto-google-cloud-firestore-admin-v1/target/site/apidocs/</location>
-                        </offlineLink>
-                    </offlineLinks>
-                </configuration>
-            </plugin>
-        </plugins>
-    </reporting>
     <build>
         <plugins>
             <plugin>