Fix ${var} deprecation warning in License model

When upgrading to php8.3 i started getting deprecation warning about
using ${var} instead of {$var} in 2 places in License.php

PHP Deprecated:  Using ${var} in strings is deprecated, use {$var} instead in /var/www/snipe-it/app/Models/License.php on line 187
PHP Deprecated:  Using ${var} in strings is deprecated, use {$var} instead in /var/www/snipe-it/app/Models/License.php on line 219

This simple fix switches the offending statements to {$var} syntax.

Author: Jeremy Price

app/Models/License.php

@@ -184,7 +184,7 @@ public static function adjustSeatCount($license, $oldSeats, $newSeats)
             $logAction->item_type = self::class;
             $logAction->item_id = $license->id;
             $logAction->created_by = auth()->id() ?: 1; // We don't have an id while running the importer from CLI.
-            $logAction->note = "deleted ${change} seats";
+            $logAction->note = "deleted {$change} seats";
             $logAction->target_id = null;
             $logAction->logaction('delete seats');
 
@@ -216,7 +216,7 @@ public static function adjustSeatCount($license, $oldSeats, $newSeats)
             $logAction->item_type = self::class;
             $logAction->item_id = $license->id;
             $logAction->created_by = auth()->id() ?: 1; // Importer.
-            $logAction->note = "added ${change} seats";
+            $logAction->note = "added {$change} seats";
             $logAction->target_id = null;
             $logAction->logaction('add seats');
         }
@@ -743,4 +743,4 @@ public function scopeOrderByCreatedBy($query, $order)
     {
         return $query->leftJoin('users as admin_sort', 'licenses.created_by', '=', 'admin_sort.id')->select('licenses.*')->orderBy('admin_sort.first_name', $order)->orderBy('admin_sort.last_name', $order);
     }
-}
+}