bug(windows): Google Sites is not working correctly with Keyman

Report at https://community.software.sil.org/t/keyman-doesnt-work-with-sites-google-com/8606.

* Firefox 124.0.1
* Windows 11 23H2
* Keyman 16.0.147.

(@mcdurdin says: I have seen different, but also inconsistent behaviour with Chrome 123 or thereabouts and Keyman 17 beta in Google Sites).

Per jheath on community forum:

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I was just trying to create a site on [sites.google.com](http://sites.google.com/), and when I typed I was getting all sorts of garbage. When I turned off my Keyman keyboard, it started working fine again.

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I’m using Firefox 124.0.1, Windows 11 23H2, Keyman 16.0.147, I’m using a new test version of Tchad QWERTY that we are developing, but the same thing happens if I use the Tchad keyboard currently in the repo.

I did a screen capture, which should be available with this link:
https://drive.google.com/file/d/1gUdgeiEjhRhHJXMY9ontVXpWnApQhG8u/view?usp=sharing
But it didn’t capture the mouse, so let me give you a guided tour...
* My Tchad QWERTY keyboard is already activated
* I start on this community page, then open the sites.google.com link above in a new tab
* From that tab I click on Blank site to start a new site
* I select the title text and change it to Arial (something that can handle Unicode better)
* I type "Test a[e] /b/n/e"
* With this keyboard, that should result in the text "Test áè ɓŋə" (but it doesn’t)
* Then I type backspace 6 times to get rid of those last 3 letters (should have only been 3 backspaces)
* Then I type "test" and those last 3 letters magically reappear

If you actually do this test, and try to click the insertion point to insert or delete characters you will see very wacky results. There is no way to "clean up" the text that was produced. I found the best way to enter the text was to type it in some other program, then copy and paste it into the Google site.