Assert replaced with throw since to avoid "unused variable" warnings in...

Assert replaced with throw since to avoid "unused variable" warnings in release mode. Also conceptually it should be throw.

GUI/coregui/mainwindow/AppSvc.cpp

@@ -43,12 +43,18 @@ ProjectManager *AppSvc::this_projectManager()
 
 void AppSvc::this_subscribe(ProjectManager *projectManager)
 {
-    Q_ASSERT(m_projectManager == nullptr);
+    if(m_projectManager != nullptr) {
+        throw GUIHelpers::Error("AppSvc::projectManager() -> Error. Attempt to subscribe "
+                                "ProjectManager twice.");
+    }
     m_projectManager = projectManager;
 }
 
 void AppSvc::this_unsubscribe(ProjectManager *projectManager)
 {
-    Q_ASSERT(m_projectManager == projectManager);
+    if(m_projectManager != projectManager) {
+        throw GUIHelpers::Error("AppSvc::projectManager() -> Error. Attempt to unsubscribe "
+                                "ProjectManager before it was subscribed.");
+    }
     m_projectManager = nullptr;
 }