bug(android): updates to lexical models offered for all languages listed in the model

The `nrc.en.mtnt` lexical model lists `en`, `en-US` and `en-CA` as languages. If the user tries to update through the "Install Updates" menu item, three confirmation dialogs are shown, one for each listed language, although only one language is installed.

## To reproduce

- install SIL EuroLatin keyboard for English
- download and install [nrc.en.mtnt model, v0.3.0](https://downloads.keyman.com/models/nrc.en.mtnt/0.3.0/nrc.en.mtnt.model.kmp) for English
- verify the version for nrc.en.mtnt model
- click the "Install Updates" menu item
- notice that three confirmation dialogs are shown

## Expected behavior

Only one confirmation dialog for the model, listing the installed (not available) languages.

## Remarks

- This bug will only show after #16266 is merged which fixes offering updates for lexical models
- See also #16277

Keyman 19.0.258-alpha-local

Start in the Android client by reproducing the update flow from the "Install Updates" menu with nrc.en.mtnt v0.3.0 installed for English. Check the interaction with the lexical model's en, en-US, and en-CA language list, and compare the behavior with the changes in #16266 and related issue #16277. Done means one confirmation dialog appears and lists only the installed language.

Written by the indexing model from the issue text.