Refactor longpress logic so key text is not confused with key code

A tchad keyboard has a diacritic rule that converts `=` (U_003D) into a combining macron (U_0304).
A longpress on `»` (U_00BB) was inadvertently triggering the diacritic rule, and outputting the macron.

The longpress code in KMEA and KMW needs to be refactored so they dont confuse key text (U_00BB is decimal 187) with underlying keyCodes (`=` is keyCode 187).

- fix KMW executePopupKey so key code is dictionary lookup instead of parsing the keyID.
- clean up JS call to executePopupKey since it only uses the keyID