Make apex availability to com.android.wifi explicit

This is done implicitly today via a baseline map in
build/soong/apex/apex.go. Make this explicit in Android.bp

Bug: 281077552
Test: m nothing
Change-Id: I71d9a6ce9707557f8e7652adc7afa3292ef9188d
diff --git a/wifi/1.2/Android.bp b/wifi/1.2/Android.bp
index f0edb81..83b156e 100644
--- a/wifi/1.2/Android.bp
+++ b/wifi/1.2/Android.bp
@@ -27,4 +27,8 @@
         "android.hidl.base@1.0",
     ],
     gen_java: true,
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.wifi",
+    ],
 }