Reset splitter sizes on database unlock

* Attempt to avoid issue with splitters not being appropriately calculated because the main window isn't sized yet. This can happen if the main window is hidden when the database is loaded and the splitter sizes are not recorded in the config file.

src/gui/DatabaseWidget.cpp

@@ -1284,6 +1284,7 @@ void DatabaseWidget::loadDatabase(bool accepted)
     }
 
     if (accepted) {
+        emit databaseAboutToUnlock();
         replaceDatabase(openWidget->database());
         switchToMainView();
         processAutoOpen();
@@ -1440,6 +1441,7 @@ void DatabaseWidget::unlockDatabase(bool accepted)
         }
     }
 
+    emit databaseAboutToUnlock();
     QSharedPointer<Database> db;
     if (senderDialog) {
         db = senderDialog->database();