Can't type words using dead keys (like "já") with imap jk Esc and iBus enabled

[awvalenti]

Describe the bug
VSCodeVim mistakes keystrokes when iBus is enabled, a composed imapping is enabled and a dead key is pressed.

To Reproduce

1. Use this on vimrc: imap jk <Esc>
2. Enable iBus (Linux)
3. Enter insert mode
4. Try to type fast: já (key j, key `, key a)
5. It displays some random text, like ´lj´ (with grave accents around, can't display them here because of markdown

Expected behavior
Display the desired word já

Screenshots

Environment (please complete the following information):

• Extension (VsCodeVim) version: 1.30.1
• VSCode version: 1.103.2
• OS: Linux Mint Cinnamon 21.3 64-bit

Additional context
Add any other context about the problem here.