refactor(web): extract suggestion-finalization block into its own function 📚

[jahorton]

After working again with the main method for generating predictions over the past few PRs, I got reminded of just how long that method is. This was further complicated after recognizing issues regarding near-match suggestion prioritization (#11876).

With a bit of effort, we should be able to spin off individual 'sections' of the predict method into their own individual functions. This would help clarify exactly what each section specifically needs and increase code clarity for future maintainers.

For simplicity of review, I'll be doing one section at a time, working from bottom-to-top. Each section has effects for those that follow it, so this should minimize the number of cross-effects for the PR set as a whole.

@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 - 18.0.60 (0.11899.11396)
• 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 18.0.75-alpha