Terminal: Fix broken selection after dbl/trp click

This commit resets the terminal triple click timer when appropriate.

Userland/Libraries/LibVT/TerminalWidget.cpp

@@ -807,6 +807,7 @@ void TerminalWidget::mousedown_event(GUI::MouseEvent& event)
         else if (m_rectangle_selection)
             m_rectangle_selection = false;
 
+        m_triple_click_timer.reset();
         update_copy_action();
         update();
     }