fix(web): add "result sanitizing" wrapper for custom wordbreakers

[jahorton]

Fixes: #16587
Fixes: #16585

Build-bot: skip release:web,android,ios

🚧 Current known issues 🚧

• On mon_anonta, the second default suggestion, when applied, will often leave the banner unaffected. Re-tapping the suggestion will yield a blank banner and duplicate the suggestion - both of which are undesired behaviors.

User Testing

TEST_KHMER_REPRO: Using Keyman for Android, the khmer_angkor keyboard, and the sil.km.gcc model, verify that #16587's repro no longer triggers the error.

1. Select ការ
2. press spacebar
3. Verify that predictions do not show words starting with ការ aside from ការ itself.
4. Verify that applying a prediction does not replace ការ.

TEST_KHMER_PREDICTIONS: Using Keyman for Android, the khmer_angkor keyboard, and the sil.km.gcc model, verify that text predictions operate smoothly.

• Use it for about 3 minutes and report any unexpected issues you encounter.
• Add double-spaces on occasion and verify that this does not impact predictive text behavior.

TEST_ANONTA: Using Keyman for Android and the mon_anonta keyboard, verify that predictions operate smoothly.

• Try repeating the same two characters as the start of a word multiple times and report any issues encountered - both in generated predictions and when applying the suggestions after those first two characters.
• Add double-spaces on occasion and verify that this does not impact predictive text behavior.

[keymanapp-test-bot]

User Test Results

Test specification and instructions

• ⬜ TEST_KHMER_REPRO (OPEN)
• ⬜ TEST_KHMER_PREDICTIONS (OPEN)
• ⬜ TEST_ANONTA (OPEN)

Results Template

# Test Results

* **TEST_KHMER_REPRO (OPEN):** notes
* **TEST_KHMER_PREDICTIONS (OPEN):** notes
* **TEST_ANONTA (OPEN):** notes

Test Artifacts

• Android
  • Keyman for Android apk
  • FirstVoices Keyboards for Android apk
  • KeyboardHarness apk
  • KMSample1 apk
  • KMSample2 apk
• Web
  • KeymanWeb Test Home