HybridWebView: Clean up duplicate path manipulization/normalization code

[Eilon]

See PR comment: https://github.com/dotnet/maui/pull/22880#discussion_r1672511444

@mattleibow said:

Can this rather use FileSystemPlatformOpenAppPackageFile instead of duplicating code?

@Eilon said:

The MAUI FileSystem APIs are unfortunately async-only (normally a good thing), but the Android API being implemented here is sync-only. For that reason I did the call directly because ultimately the low-level file system API on Android is sync anyway (just regular file system call). I have been unable to find a pattern to do async interception of Android WebView requests.

@mattleibow said:

Can we create an issue to track this, we already have FileSystemUtils.NormalizePath so we probably should create a helper for this and use it everywhere vs copying in all places.