fix: shortcut keys for power users

[bhattdevarsh]

https://github.com/agritheory/check_run/issues/190

• Press ↑ arrow to move up in the row.
• Press ↓ arrow to move down in the row.
• Press Enter to enter the focused row's mode of payment.
• Press Esc to come out of mode of payment.
• Press Tab to regain the focus on rows.

https://github.com/agritheory/check_run/assets/58166671/f3f88465-0fbf-4d32-a3c2-45ebc6862ba9

[Alchez]

@bhattdevarsh I don't see any event listeners for the enter, tab and escape characters. And I get the following error while trying to press space on the 'Pay' button:

TypeError: Cannot read properties of undefined (reading '3')
    at updateSelectedRow (check_run.js:5838:29)
    at fn._withMods.fn._withMods (check_run.js:5512:14)
    at fn._withKeys.fn._withKeys (check_run.js:5531:16)
    at check_run.js:5302:62
    at callWithErrorHandling (check_run.js:1157:20)
    at callWithAsyncErrorHandling (check_run.js:1165:19)
    at callWithAsyncErrorHandling (check_run.js:1175:19)
    at HTMLTableRowElement.invoker (check_run.js:5284:7)

which is failing at the following line:

event.target.cells[3].firstChild.focus();