Remove primary configuration preference

It is no longer used.

Signed-off-by: Samuel Holland <samuel@sholland.org>

app/src/main/res/values/strings.xml

@@ -52,8 +52,6 @@
     <string name="persistent_keepalive">Persistent keepalive</string>
     <string name="placeholder_text">No configuration selected</string>
     <string name="pre_shared_key">Pre-shared key</string>
-    <string name="primary_config">Quick tile configuration</string>
-    <string name="primary_config_summary">This configuration will be controlled by the quick settings tile</string>
     <string name="private_key">Private key</string>
     <string name="public_key">Public key</string>
     <string name="public_key_copied_message">Public key copied to clipboard</string>

app/src/main/res/xml/preferences.xml

@@ -1,9 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
-    <com.wireguard.android.preference.TunnelListPreference
-        android:key="primary_config"
-        android:summary="@string/primary_config_summary"
-        android:title="@string/primary_config" />
     <CheckBoxPreference
         android:defaultValue="false"
         android:key="restore_on_boot"