Remove <groupId>org.apache.maven.plugins</groupId>.

It is [the default for plugins](https://maven.apache.org/guides/mini/guide-configuring-plugins.html#Introduction).

RELNOTES=n/a
PiperOrigin-RevId: 793718324

Author: cpovirk

pom.xml

@@ -142,7 +142,6 @@
         <version>3.21.0</version>
       </plugin>
       <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <version>3.5.3</version>
         <configuration>
@@ -199,7 +198,6 @@
       <build>
         <plugins>
           <plugin>
-            <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-gpg-plugin</artifactId>
             <version>3.2.8</version>
             <executions>
@@ -211,7 +209,6 @@
             </executions>
           </plugin>
           <plugin>
-            <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-source-plugin</artifactId>
             <version>3.3.1</version>
             <executions>
@@ -222,7 +219,6 @@
             </executions>
           </plugin>
           <plugin>
-            <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-javadoc-plugin</artifactId>
             <version>3.11.2</version>
             <executions>