fix(web): fix handling of data: url fonts, fonts with single quotes in filename

[jahorton]

Fixes: #13018
Fixes: #13022

Our fontface-defining stylesheet format has been using single-quotes to enclose the filename. Sadly, encodeURI doesn't mangle single-quotes - it mangles double-quotes instead. So, we should adjust the quote type used there.

Fixed stylesheet:

@font-face {
font-family:soninke_n_ti;
font-style:normal;
font-weight:normal;
src:url("./N'tiFont.otf") format('truetype');
}

When using the KMP loader to diagnose the problem, I found that data URLs were handled... to a point, and then that process was unnecessarily aborted. That was simple enough to fix with the first commit of this PR.

User Testing

This is how the default layer of the keyboard looks in desktop-mode Keyman Engine for Web:

• TEST_ANDROID: Using the Android test build from this PR and the soninke_n_ti.kmp package from https://jahorton.github.io/soninke_n_ti.kmp, verify that the keyboard loads properly and has proper characters for its font.

• TEST_IOS: Using the Android test build from this PR and the soninke_n_ti.kmp package from https://jahorton.github.io/soninke_n_ti.kmp, verify that the keyboard loads properly and has proper characters for its font.

[keymanapp-test-bot]

User Test Results

Test specification and instructions

• ⬜ TEST_ANDROID (OPEN)
• ⬜ TEST_IOS (OPEN)

Results Template

# Test Results

* **TEST_ANDROID (OPEN):** notes
* **TEST_IOS (OPEN):** notes

Test Artifacts

• Android
  • Keyman for Android apk
  • FirstVoices for Android 16.0 apk
  • FirstVoices Keyboards for Android apk
  • KeyboardHarness apk
  • Keyman for Android 16.0 apk
  • KMSample1 apk
  • KMSample2 apk
• Developer
  • Keyman Developer
  • Compiler Regression Tests
  • kmcomp.zip
• iOS
  • Keyman for iOS (simulator image)
  • FirstVoices Keyboards for iOS (simulator image)
  • TestFlight internal PR build version - 18.0.177 (0.13032.12686)
• Keyboards
  • Test Keyboards
• Web
  • KeymanWeb Test Home
• Windows
  • Keyman for Windows
  • FirstVoices Keyboards for Windows
  • Text Editor (32 bit)
  • Text Editor (64 bit)

[mcdurdin]

Fixes: 13017

I don't think this is true -- that's a separate Keyman Developer bug

[mcdurdin]

LGTM

[jahorton]

Fixes: 13017

I don't think this is true -- that's a separate Keyman Developer bug

You think there's something else on that side of things, past the Web issues that'd probably also affect the behavior?

[mcdurdin]

Fixes: 13017

I don't think this is true -- that's a separate Keyman Developer bug

You think there's something else on that side of things, past the Web issues that'd probably also affect the behavior?

Yes. Take a look at PR #13020 associated with #13017 which already fixed the issue 😁 Font filenames are rewritten by Keyman Developer Server (for reasons relating to how fonts are made available in the dev environment...), so the quote issue cannot arise there in the uri.

[jahorton]

Force-pushed to remove the link to an issue not actually fixed by this PR.