fix(ui/treeview): dismiss right-click context menu when a menu item runs

The custom right-click context menu didn't close after a menu item
opened a modal dialog (e.g. "Compose into…"), leaving the menu
floating behind the modal until the user clicked elsewhere or hit
Escape. Add @onclick="DismissContextMenu" on the menu container so
any click inside it (button, divider, padding) closes the menu after
the button's own handler bubbles up.

src/ScadaLink.CentralUI/Components/Shared/TreeView.razor

@@ -23,6 +23,7 @@ else
 {
     <div class="tv-ctx-overlay" @onclick="DismissContextMenu" style="position:fixed;top:0;left:0;width:100vw;height:100vh;z-index:1049;background:transparent;"></div>
     <div class="dropdown-menu show" tabindex="-1" @ref="_contextMenuRef" @onkeydown="OnContextMenuKeyDown"
+         @onclick="DismissContextMenu"
          style="position:fixed;top:@(_contextMenuY)px;left:@(_contextMenuX)px;z-index:1050;outline:none;">
         @ContextMenu(_contextMenuItem)
     </div>