UI: Remove allProjectors list

Seems like this wasn't used anywhere and projectors were not being
removed on destruction, resulting in a memory leak.

UI/window-projector.cpp

@@ -11,7 +11,6 @@
 #include "multiview.hpp"
 
 static QList<OBSProjector *> multiviewProjectors;
-static QList<OBSProjector *> allProjectors;
 
 static bool updatingMultiview = false, mouseSwitching, transitionOnDoubleClick;
 
@@ -89,8 +88,6 @@ OBSProjector::OBSProjector(QWidget *widget, obs_source_t *source_, int monitor,
 	if (source)
 		obs_source_inc_showing(source);
 
-	allProjectors.push_back(this);
-
 	ready = true;
 
 	show();
@@ -300,8 +297,6 @@ void OBSProjector::EscapeTriggered()
 {
 	OBSBasic *main = reinterpret_cast<OBSBasic *>(App()->GetMainWindow());
 	main->DeleteProjector(this);
-
-	allProjectors.removeAll(this);
 }
 
 void OBSProjector::UpdateMultiview()