Add platform_apis in Android.bp

platform_apis must be true when sdk_version is empty.
So add platform_apis into file that is not included it.

Bug: 132780927
Test: m
Change-Id: Ie7badd61248bbabaf51ef8fb30bdd832af88da15
diff --git a/packages/SystemUI/plugin/ExamplePlugin/Android.bp b/packages/SystemUI/plugin/ExamplePlugin/Android.bp
index a0eaf14..c6c80f3 100644
--- a/packages/SystemUI/plugin/ExamplePlugin/Android.bp
+++ b/packages/SystemUI/plugin/ExamplePlugin/Android.bp
@@ -11,4 +11,5 @@
 
     srcs: ["src/**/*.java"],
 
+    platform_apis: true,
 }