[HOTFIX][BUILD][TEST-MAVEN] Remove duplicate dependency

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #10868 from zsxwing/hotfix-akka-pom.

external/akka/pom.xml

@@ -48,6 +48,10 @@
       <type>test-jar</type>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.spark</groupId>
+      <artifactId>spark-test-tags_${scala.binary.version}</artifactId>
+    </dependency>
     <dependency>
       <groupId>${akka.group}</groupId>
       <artifactId>akka-actor_${scala.binary.version}</artifactId>
@@ -58,13 +62,6 @@
       <artifactId>akka-remote_${scala.binary.version}</artifactId>
       <version>${akka.version}</version>
     </dependency>
-    <dependency>
-      <groupId>org.apache.spark</groupId>
-      <artifactId>spark-core_${scala.binary.version}</artifactId>
-      <version>${project.version}</version>
-      <type>test-jar</type>
-      <scope>test</scope>
-    </dependency>
   </dependencies>
   <build>
     <outputDirectory>target/scala-${scala.binary.version}/classes</outputDirectory>