bug(web): text entered from keyboard help page doesn't trigger predictive text

> * TEST_PRED_TEXT_SUGGEST_WEB (FAILED):
> Device specifications: Windows 10 in Bootcamp. The results are as followed:
>
> Navigate to "Prediction - robust testing" on Chrome v138.0.7204.
> Verification: The predictive text did not suggest word until the next key typed, video shown:

https://github.com/user-attachments/assets/e8c538cf-31e8-4628-b57e-15bf13802e6c

Ooh, that's a new one! It's not actually related to this PR, though - sorry I didn't spec the test super well.

It looks like any text entered via interaction with the help page fails to trigger predictions. Definitely worth noting as a bug.

_Originally posted by @jahorton in https://github.com/keymanapp/keyman/issues/14440#issuecomment-3160271031_

Note that we don't publicly publish predictive text for desktop-keyboard layouts yet... so this shouldn't actually impact any end users at this time.