Feat: Add warning for conflicting group permissions

This change introduces a visual warning in the group settings page. The warning appears when an admin attempts to disable a permission for a group that is already enabled in the default 'user' group. This is necessary because permissions are additive, and disabling a permission in a specific group will not revoke it if it's enabled in the default group.

To achieve this, the following changes were made:
- A new `PermissionSwitch.svelte` component was created to encapsulate the permission switch and its warning logic, avoiding redundant code.
- The `Groups.svelte` component was updated to correctly fetch the default user group's permissions.
- The `Permissions.svelte` component was refactored to use the new `PermissionSwitch.svelte` component, making the code cleaner and more maintainable.

src/lib/components/admin/Users/Groups/GroupItem.svelte

@@ -17,6 +17,7 @@
 		name: 'Admins',
 		user_ids: [1, 2, 3]
 	};
+	export let defaultPermissions = {};
 
 	export let setGroups = () => {};
 
@@ -59,6 +60,7 @@
 	edit
 	{users}
 	{group}
+	{defaultPermissions}
 	onSubmit={updateHandler}
 	onDelete={deleteHandler}
 />