Change uuid field to String type due to new format UUIDs that fail to parse on GFE 3.16

app/src/main/java/com/limelight/preferences/ConfirmDeleteOscPreference.java

@@ -3,7 +3,6 @@ package com.limelight.preferences;
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.DialogInterface;
-import android.content.SharedPreferences;
 import android.os.Build;
 import android.preference.DialogPreference;
 import android.util.AttributeSet;