refactor: Use ActivityService to create system messages in seeder

app/Models/PredefinedMutation.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class PredefinedMutation extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'dynamic_id',
+        'name',
+        'description',
+        'amount',
+        'type',
+    ];
+
+    public function dynamic(): BelongsTo
+    {
+        return $this->belongsTo(Dynamic::class);
+    }
+}