chore: include showcase module in test coverage report (#1548)

* chore: add showcase classes to test coverage

Author: mpeddada1

coverage-report/README.md

@@ -10,7 +10,7 @@ In order to view aggregate unit test coverage of api-common and GAX in `api-comm
 1. At the root of the repository, run `mvn clean test -DenableTestCoverage`.
 2. The metrics can be found at `gapic-generator-java/coverage-report/target/site/jacoco-aggregate/index.html`
 
-![Screenshot 2023-03-21 at 12 25 41 PM](https://user-images.githubusercontent.com/66699525/226675190-5225e778-99d4-44d0-8177-29d48d1c35ee.png)
+![Screenshot 2023-03-23 at 4 29 36 PM](https://user-images.githubusercontent.com/66699525/227346653-b50ec440-71f9-49f4-be21-3976c7f995c7.png)
 
 ### Integration Test Coverage
 
@@ -19,4 +19,4 @@ In order to view aggregate integration test coverage of api-common and GAX in `a
 1. At the root of the repository, run `mvn clean verify -DskipUnitTests -DenableTestCoverage -Penable-integration-tests`.
 2. The metrics can be found at `gapic-generator-java/coverage-report/target/site/jacoco-aggregate/index.html`
 
-![Screenshot 2023-03-21 at 12 26 26 PM](https://user-images.githubusercontent.com/66699525/226675461-97a1c4b5-a90f-470d-b0c8-51e63a35a548.png)
+![Screenshot 2023-03-23 at 4 33 11 PM](https://user-images.githubusercontent.com/66699525/227348487-f1ba2bb8-7577-4280-a1a1-7aa78e242f12.png)

coverage-report/pom.xml

@@ -27,7 +27,6 @@
                 <groupId>com.google.cloud</groupId>
                 <artifactId>gapic-showcase</artifactId>
                 <version>0.0.1-SNAPSHOT</version>
-                <scope>test</scope>
             </dependency>
             <dependency>
                 <groupId>com.google.api</groupId>

showcase/pom.xml

@@ -27,7 +27,6 @@
     <checkstyle.skip>true</checkstyle.skip>
     <clirr.skip>true</clirr.skip>
     <enforcer.skip>true</enforcer.skip>
-    <skipUnitTests>true</skipUnitTests>
   </properties>
 
   <dependencyManagement>
@@ -74,8 +73,16 @@
           <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-surefire-plugin</artifactId>
+            <version>3.0.0-M8</version>
             <configuration>
-              <skip>${skipUnitTests}</skip>
+              <!-- Exclude MessagingClientHttpJsonTest which is currently failing.
+              See https://github.com/googleapis/gapic-generator-java/issues/1547 -->
+              <!-- TODO(1547): Remove this exclusion once MessagingClientHttpJsonTest#updateBlurbTest is fixed -->
+              <excludes>
+                <exclude>**/MessagingClientHttpJsonTest.java</exclude>
+              </excludes>
+              <reportNameSuffix>sponge_log</reportNameSuffix>
+              <skipTests>${skipUnitTests}</skipTests>
             </configuration>
           </plugin>
           <plugin>