ci: wrap nexus-staging-maven-plugin with a profile (#7059)

The profile matches java-shared-config.
https://github.com/googleapis/java-shared-config/blob/main/native-image-shared-config/pom.xml#L112

Author: suztomo

google-cloud-bom/pom.xml

@@ -258,18 +258,22 @@
   </dependencyManagement>
 
   <build>
+    <pluginManagement>
+      <plugins>
+        <plugin>
+          <groupId>org.sonatype.plugins</groupId>
+          <artifactId>nexus-staging-maven-plugin</artifactId>
+          <version>1.7.0</version>
+          <extensions>true</extensions>
+          <configuration>
+            <serverId>sonatype-nexus-staging</serverId>
+            <nexusUrl>https://google.oss.sonatype.org/</nexusUrl>
+            <autoReleaseAfterClose>false</autoReleaseAfterClose>
+          </configuration>
+        </plugin>
+      </plugins>
+    </pluginManagement>
     <plugins>
-      <plugin>
-        <groupId>org.sonatype.plugins</groupId>
-        <artifactId>nexus-staging-maven-plugin</artifactId>
-        <version>1.7.0</version>
-        <extensions>true</extensions>
-        <configuration>
-          <serverId>sonatype-nexus-staging</serverId>
-          <nexusUrl>https://google.oss.sonatype.org/</nexusUrl>
-          <autoReleaseAfterClose>false</autoReleaseAfterClose>
-        </configuration>
-      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-site-plugin</artifactId>
@@ -331,6 +335,27 @@
   </reporting>
 
   <profiles>
+    <profile>
+      <!-- By default, we release artifacts to Sonatype, which requires
+          nexus-staging-maven-plugin. -->
+      <id>release-sonatype</id>
+      <activation>
+        <property>
+          <!-- Only when we use the release-gcp-artifact-registry profile,
+          which comes with artifact-registry-url property, this profile is
+          turned off. -->
+          <name>!artifact-registry-url</name>
+        </property>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.sonatype.plugins</groupId>
+            <artifactId>nexus-staging-maven-plugin</artifactId>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
     <profile>
       <id>release</id>
       <activation>

libraries-bom/pom.xml

@@ -93,18 +93,22 @@
   </dependencyManagement>
 
   <build>
+    <pluginManagement>
+      <plugins>
+        <plugin>
+          <groupId>org.sonatype.plugins</groupId>
+          <artifactId>nexus-staging-maven-plugin</artifactId>
+          <version>1.7.0</version>
+          <extensions>true</extensions>
+          <configuration>
+            <serverId>sonatype-nexus-staging</serverId>
+            <nexusUrl>https://google.oss.sonatype.org/</nexusUrl>
+            <autoReleaseAfterClose>false</autoReleaseAfterClose>
+          </configuration>
+        </plugin>
+      </plugins>
+    </pluginManagement>
     <plugins>
-      <plugin>
-        <groupId>org.sonatype.plugins</groupId>
-        <artifactId>nexus-staging-maven-plugin</artifactId>
-        <version>1.7.0</version>
-        <extensions>true</extensions>
-        <configuration>
-          <serverId>sonatype-nexus-staging</serverId>
-          <nexusUrl>https://google.oss.sonatype.org/</nexusUrl>
-          <autoReleaseAfterClose>false</autoReleaseAfterClose>
-        </configuration>
-      </plugin>
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>flatten-maven-plugin</artifactId>
@@ -117,6 +121,27 @@
     </plugins>
   </build>
   <profiles>
+    <profile>
+      <!-- By default, we release artifacts to Sonatype, which requires
+          nexus-staging-maven-plugin. -->
+      <id>release-sonatype</id>
+      <activation>
+        <property>
+          <!-- Only when we use the release-gcp-artifact-registry profile,
+          which comes with artifact-registry-url property, this profile is
+          turned off. -->
+          <name>!artifact-registry-url</name>
+        </property>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.sonatype.plugins</groupId>
+            <artifactId>nexus-staging-maven-plugin</artifactId>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
     <profile>
       <id>release</id>
       <activation>