[WASM] ms-appx:// fonts are not parsed properly

[jeromelaban]

I'm submitting a...

• Bug report

Current behavior

A font defined as follows:

## Expected behavior
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## Minimal reproduction of the problem with instructions
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For bug reports please provide a *MINIMAL REPRO PROJECT* and the *STEPS TO REPRODUCE*
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## Environment
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Nuget Package:

Package Version(s):

Affected platform(s):

• iOS
• Android
• WebAssembly
• Windows
• Build tasks

Visual Studio

• 2017 (version: )
• 2019 (version: )
• for Mac (version: )

Relevant plugins

• Resharper (version: )

[MartinZikmund]

I have hit this thing when working on my app so I will fix it

[MartinZikmund]

Done.