fix(web): support SVG elements when checking className

[mcdurdin]

Fixes #11364.

Instead of using className which may be of type SVGAnimatedString if the element is an SVG element, use getAttribute('class'). As that function can return null if the class attribute is not defined, use optional chaining to avoid a new error...

Uses the same pattern in hardwareEventKeyboard.ts, although I suspect the problem may never arise there.

I audited the uses of className in our KeymanWeb source and found only these three instances which may be problematic. I have not searched elsewhere.

@keymanapp-test-bot skip

[keymanapp-test-bot[bot]]

User Test Results

Test specification and instructions

User tests are not required

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 - 17.0.320 (0.11365.10898)
• Keyboards
  • Test Keyboards
• Web
  • KeymanWeb Test Home
• Windows
  • Keyman for Windows
  • FirstVoices Keyboards for Windows
  • Text Editor (32 bit)
  • Text Editor (64 bit)

[keyman-server]

Changes in this pull request will be available for download in Keyman version 17.0.320-beta