bug(windows): numberpad keys "/, *, -, +" are either not being added or resetting the context in non-compliant apps

In testing #11172 it was discovered we currently don't handle the numberpad keys "/;*;-;+" well in non-compliant apps. The context is either reset when they are pressed or not added to the context at all.

Steps to preproduce.

Non-compliant
Load euro-latin keyboard
1. Press 1
2. Using the number pad press / /
3. Press 2
The result is:
1//2
instead of:
½

Non-compliant context reset

1. Press a
2. Using the number pad press \*
the result is:
a\*
instead of:
`Star`