feat(web): support phrase predictions

**Is your feature request related to a problem? Please describe.**

From a team review of the Keyman for Android UX (#7161)

At a minimum, phrase predictions are needed, rather than isolated word-by-word. More sophisticated models are really what we need, though, which is a major project. Still, if we don't make note it, it won't happen?

Per @jahorton:

* [JH] Fortunately, I left some hooks & design work in to help facilitate this. Definitely not enough to solve it outright, though.

**Related issues**

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**Keyman for Windows/macOS/Linux/iPhone/iPad/Android:**
- Device: Samsung A90 5G
- OS: Android 12
- Keyman version: 15.0.269-stable