apex_set is force disabled when necessary

prebuilt_apex has been disabled when the device is configured for
flattened APEXes, sanitized, instrumented, or built unbundled. However,
apex_set which is another type of APEX prebuilt wasn't disabled for the
same conditions.

This change fixes the discripency. apex_set modules are also force
disabled when the prebuilts are not expected.

Bug: 161316762
Bug: 160933444
Test: OVERRIDE_TARGET_FLATTEN_APEX=true m
The built image has only the flattened APEXes and the device boots

Change-Id: I6c90dfb28d565861a473a1bdce93269ec370601d

apex/apex.go

@@ -2112,7 +2112,7 @@ func (a *apexBundle) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 			case android.PrebuiltDepTag:
 				// If the prebuilt is force disabled, remember to delete the prebuilt file
 				// that might have been installed in the previous builds
-				if prebuilt, ok := child.(*Prebuilt); ok && prebuilt.isForceDisabled() {
+				if prebuilt, ok := child.(prebuilt); ok && prebuilt.isForceDisabled() {
 					a.prebuiltFileToDelete = prebuilt.InstallFilename()
 				}
 			}