remove java-iam module from sdk-platform-java parent

Author: chingor13

sdk-platform-java/pom.xml

@@ -19,7 +19,6 @@
     <module>api-common-java</module>
     <module>gax-java</module>
     <module>gapic-generator-java</module>
-    <module>java-iam</module>
     <module>java-core</module>
     <module>gapic-generator-java-bom</module>
     <module>java-shared-dependencies</module>