Fix CSS Hot Reload on iOS device

[spadapet]

Description of Change

This fixes a bug with:

• MAUI Blazor Hybrid apps
• Open in Visual Studio 2022
• Using Pair to Mac to debug on a Mac
• Hot reload CSS on iOS Simulator

Hot reloading CSS didn't work because the web view on iOS didn't refresh the CSS since the href didn't change. The CSS link looks like:

• <link rel="stylesheet" href="app.css" />

And when the CSS file changed, the href was modified by adding an empty string to it. The browser in iOS didn't detect any change in the href (since the change was a no-op) and didn't refresh the CSS. On Windows and Android the browser would still refresh CSS when the href had a no-op change.

My fix is to make a real change to the CSS link's href by appending a query string with a timestamp to it. Now all the browsers refresh the CSS since the timestamp is always unique.

Issues Fixed

Bug 1821555: [XVS][MAUI] CSS Hot reload on iOS Simulator not working

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src/BlazorWebView/src/SharedSource/StaticContentHotReloadManager.cs:32

• Ensure that there is a test case verifying that the CSS reloads correctly with the new timestamp query string.

allLinkElems.forEach(elem => elem.href = elem.href.split('?')[0] + '?reload_version=' + Date.now());

[spadapet]

Ping for code review: @dotnet/dotnet-maui-blazor-eng