Allow ActivityEmbedding in APEX modules.

Also this lib uses HTTP and doesn't declare it, so after manifest merge
the APEX module won't build.  Add the uses-library.

Bug: 253394518
Test: test builds
Change-Id: I94cb2be58d88521ed10e4fba5b5e11169bead624

packages/SettingsLib/ActivityEmbedding/Android.bp

@@ -26,4 +26,9 @@ android_library {
         "androidx.window.extensions",
         "androidx.window.sidecar",
     ],
+
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.permission",
+    ],
 }

packages/SettingsLib/ActivityEmbedding/AndroidManifest.xml

@@ -21,6 +21,7 @@
     <uses-sdk android:minSdkVersion="21" />
 
     <application>
+        <uses-library android:name="org.apache.http.legacy" android:required="false" />
         <uses-library android:name="androidx.window.extensions" android:required="false" />
         <uses-library android:name="androidx.window.sidecar" android:required="false" />
     </application>