bug(web): wrong output with Caps Lock on hardware keyboard

[ermshiperete]

With a mnemonic keyboard, e.g. SIL Philippines, having caps lock on is inconsistent between OSK and hardware keyboard.

Input	Expected Output
a	a
1	1
Shift+a	A
Shift+1	!

With Caps Lock on:

Input	Expected Output
a	A
1	1
Shift+a	a
Shift+1	!

This works correctly when typing on the OSK.
However, when typing on the hardware keyboard you get different results. Pressing Caps Lock on the hardware keyboard will toggle the Caps Lock-LED on the hardware keyboard and also toggle the Caps button on the OSK.

Typing on the OSK then gives the expected results for Caps Lock. Typing on the hardware keyboard gives the non-CapsLock outputs:

With Caps Lock on:

Input on hardware keyboard	Actual Output	Expected Output
a	a	A
1	1	1
Shift+a	A	a
Shift+1	!	!

With a positional keyboard, e.g. US Basic things work like expected.

Possibly related: #5456
See also also the discussion in #15343.