UMG: Add flag to call UserWidget::OnInitialized. It would be preferable to not have that flag, like PreConstruct, Construct and Destruct but there is too much deprecation to handle.

#jira UE-191195
#rb editor-ui-systems

[CL 27268113 by patrick boutot in ue5-main branch]

Engine/Source/Editor/UMGEditor/Private/WidgetBlueprintCompiler.cpp

@@ -1124,6 +1124,8 @@ void FWidgetBlueprintCompilerContext::FinishCompilingClass(UClass* Class)
 		}
 	}
 
+	BPGClass->bCanCallInitializedWithoutPlayerContext = WidgetBP->bCanCallInitializedWithoutPlayerContext;
+
 	Super::FinishCompilingClass(Class);
 
 	CA_ASSUME(BPGClass);