internal: Further unsafe state improvements (#3404)

Instead of allowing Hyprland to sit in a state where there are no monitors, which various parts of the code don't like, we create a fake headless output on all monitor disconnect, and then remove it when a monitor appears

src/helpers/Monitor.cpp

@@ -243,7 +243,7 @@ void CMonitor::onDisconnect() {
 
     if (!BACKUPMON) {
         Debug::log(WARN, "Unplugged last monitor, entering an unsafe state. Good luck my friend.");
-        g_pCompositor->m_bUnsafeState = true;
+        g_pCompositor->enterUnsafeState();
     }
 
     if (BACKUPMON) {