bug(ios): double-tap on shift key does not give two click sounds

>> 2. Double-tap the shift key. Watch how it switches to a Caps layer (see the 'shiftlock' style of the Shift key).

> Working OK, but the weird thing is the double tap seem unnatural to the touch. You don't hear the two taps, just one is heard. :/

_Originally posted by @MakaraSok in https://github.com/keymanapp/keyman/issues/5989#issuecomment-997633545_