[WinUI3] Support continuous mouse event from web content to the native window

Is your feature request related to a problem? Please describe.
I create a small webapp that allows dragging to arrange the shapes (https://d2phap.github.io/shape-arrangement/), and I want to bring this to Webview2. However, the mouse event is not captured when I move the cursor out of the Webview2
Steps:

• Click and hold on a shape
• Still hold and drag the shape
• Move cursor out of the window (or the Webview2)
• The shape is not followed the cursor anymore

Describe the solution you'd like and alternatives you've considered

• There should be an API / option to allow the cursor continue to capture out of the webview2
• This will remove the gap of native app and webview2 app

AB#33613498

Start by reproducing the drag scenario in the WinUI3 WebView2 web content and observe where mouse capture stops when the cursor leaves the WebView2 or native window. Define completion as continuous delivery of the drag-related mouse events outside the webview, with no source files or tests named in the issue to guide implementation.