fix(windows): fix data url html encoding issue

[huangmingg]

closes #8760

Goal here

• Introduce DataUrl as a new WebViewUrl variant. This is because while data url strings work with existing variants, it does not really belong to any of it.
• Change url field of PendingWebview from String to Url, as the method to build a webview differ depending on the kind of URL.
• Pass the html string in a raw format to WRY, and let WRY handle the encoding instead.

WIP

• Right now it requires users to pass in encoded strings to properly work. Perform that operation in tauri directly
• Able to clean up the html helper functions, and perhaps separate html from url, similar to what WRY is doing

Tested on windows: