Prevent issue: $instance must not be accessed before initialization (#2578)

* Prevent issue:  must not be accessed before initialization

* Fix styling

* Fix styling

---------

Co-authored-by: CaReS0107 <[email protected]>

Author: CaReS0107

Diff for: src/SchedulerManager.php

@@ -24,7 +24,7 @@ public function run(): void
 
     public function __destruct()
     {
-        if (! $this->instance->wasRecentlyCreated) {
+        if ($this->instance && ! $this->instance->wasRecentlyCreated) {
             $this->instance->save();
         }
     }

Diff for: tests/Feature/Models/MailatorScheduleTest.php

@@ -62,7 +62,7 @@ public function test_can_use_carbon_target_date_before(): void
 
         //        MailatorSchedule::run();
         //        Mail::assertNothingSent();
-      
+
         $this->travelTo(now()->addDays(6));
         MailatorSchedule::run();