feat: remove unused delta time api

Author: zaucy

Source/Ecsact/Public/EcsactUnreal/EcsactExecution.cpp

@@ -4,12 +4,6 @@
 #include "EcsactGameInstanceSubsystem.h"
 #include "Engine/GameInstance.h"
 
-float EcsactUnrealExecution::DeltaTime_ = 0.f;
-
-auto EcsactUnrealExecution::DeltaTime() -> float {
-	return DeltaTime_;
-}
-
 auto EcsactUnrealExecution::Runner( //
 	class UWorld* World
 ) -> TWeakObjectPtr<class UEcsactRunner> {

Source/Ecsact/Public/EcsactUnreal/EcsactExecution.h

@@ -9,15 +9,6 @@ class ECSACT_API EcsactUnrealExecution {
 	static float DeltaTime_;
 
 public:
-	/**
-	 * Get the DeltaTime for the current EcsactRunner execution. This should be
-	 * used by Ecsact systems that are built by unreal build tool.
-	 *
-	 * NOTE: This is a workaround until 'execution metadata' is available.
-	 * SEE: https://github.com/ecsact-dev/ecsact_parse/issues/163
-	 */
-	static auto DeltaTime() -> float;
-
 	/**
 	 * Gets the runner for the given world.
 	 *

Source/Ecsact/Public/EcsactUnreal/EcsactSyncRunner.cpp

@@ -24,8 +24,6 @@ auto UEcsactSyncRunner::Tick(float DeltaTime) -> void {
 		return;
 	}
 
-	EcsactUnrealExecution::DeltaTime_ = DeltaTime;
-
 	if(registry_id == ECSACT_INVALID_ID(registry)) {
 		if(ecsact_create_registry) {
 			UE_LOG(