fix tests-spark310+ dependency (#3671)

Signed-off-by: Peixin Li <pxli@nyu.edu>

tests-spark310+/pom.xml

@@ -63,6 +63,7 @@
             <groupId>com.nvidia</groupId>
             <artifactId>rapids-4-spark-tests_${scala.binary.version}</artifactId>
             <version>${project.version}</version>
+            <type>test-jar</type>
             <classifier>${spark.version.classifier}tests</classifier>
             <scope>test</scope>
         </dependency>