Remove CosuApp.

CosuApp has not been updated in 5 years and was never released
publicly.

Test: ./gradlew assemble
Change-Id: Ibc770fea3bf6225c9f41329559d7fe31d412edf2

Author: jscott1989

settings.gradle

@@ -1,4 +1,2 @@
 include ':TestDPC'
-project(':TestDPC').projectDir = new File(rootDir, "vendor/unbundled_google/packages/TestDPC/app")
-include ':CosuApp'
-project(':CosuApp').projectDir = new File(rootDir, "vendor/unbundled_google/packages/TestDPC/cosuapp")
+project(':TestDPC').projectDir = new File(rootDir, "vendor/unbundled_google/packages/TestDPC/app")