Remove unnecessary, deprecated sharedUserId with system

sharedUserId is a deprecated flag [1] that muddies the waters when it
comes to enforcement of various policies and permissions. QcRilAm
doesn't use any and operates just fine within normal app boundaries
(uses public APIs, doesn't need any permissions outside "normal" ones,
and accesses vendor services properly over Binder).
This also allows the signing key to differ from platform, where other
android.uid.system apps are signed with.

[1] https://developer.android.com/guide/topics/manifest/manifest-element#uid

Signed-off-by: MarijnS95 <marijns95@gmail.com>

AndroidManifest.xml

@@ -2,7 +2,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.sony.qcrilam"
     coreApp="true"
-    android:sharedUserId="android.uid.system"
     android:versionCode="1"
     android:versionName="1.0" >