Updated pom.xml to enable Jacoco output (#1175)

Author: LeeParrishMSFT

libraries/bot-dialogs/pom.xml

@@ -164,7 +164,7 @@
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <configuration>
-          <argLine>-Dfile.encoding=UTF-8</argLine>
+          <argLine>${argLine} -Dfile.encoding=UTF-8</argLine>
         </configuration>
       </plugin>
     </plugins>