Task: Remove currentTick parameter (#3498)

This parameter is not used for the vast majority of task use cases and just serves as extra useless boilerplate code, especially for closure-based tasks.
This use case can be replaced using Server->getTick() in the cases where it matters.

src/scheduler/Task.php

@@ -60,7 +60,7 @@ abstract class Task{
 	 *
 	 * @return void
 	 */
-	abstract public function onRun(int $currentTick);
+	abstract public function onRun();
 
 	/**
 	 * Actions to execute if the Task is cancelled