archwiki: LocalSettings.php: give registered users the 'writeapi' right

Adding/removing pages from the whitelist when using the Vector skin requires the write API now.

Without this, regular users get this error:

You're not allowed to edit this wiki through the API.

A user reported this issue in #archlinux-wiki.

/cc @archlinux/teams/wiki/admins

roles/archwiki/templates/LocalSettings.php.j2

@@ -278,11 +278,8 @@ $wgGroupPermissions['privileged']['editprotected2'] = true;
 
 # disable user account creation via API
 $wgAPIModules['createaccount'] = 'ApiDisabled';
-# remove 'writeapi' right from users
+# remove 'writeapi' right from unregistered users
 $wgGroupPermissions['*']['writeapi'] = false;
-$wgGroupPermissions['user']['writeapi'] = false;
-# add 'writeapi' to autoconfirmed users
-$wgGroupPermissions['autoconfirmed']['writeapi'] = true;
 # stricter conditions for 'autoconfirmed' promotion
 $wgAutoConfirmAge = 86400*3; // three days
 # require at least 20 normal edits before granting the 'writeapi' right