Prevent global keydown event when ContentEditable handled ENTER

[nikku]

Proposed Changes

This fixes a regression introduced via a6dfc16.

The prior change switched to onKeyDown, which is an synthetic event handler that cannot prevent default (on global clicks).

What we need to prevent default (global) clicks is actual DOM event handling. Quoting from the Inferno documentation 1:

Lower case events will bypass Inferno's event system in favour of
using the native event system supplied by the browser.

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The fixed behavior can be inspected via npm start, using the Dish Decision JavaScript field, but also in the fact that the test suite passes (again):

Checklist

To ensure you provided everything we need to look at your PR:

• Brief textual description of the changes present
• Visual demo attached
• Steps to try out present, i.e. using the @bpmn-io/sr tool
• Related issue linked via Closes {LINK_TO_ISSUE} or Related to {LINK_TO_ISSUE}

[nikku]

Rebased on top of fixed develop. Let's not squash things without adjusting to a conventional commit.

CC @jarekdanielak.

[barmac]

I find it super confusing that Inferno supports both lowercase and camelcase event handlers. Anyway, thanks for fixing this!

[barmac]

I've added comments which should save us some WTF in the future.

[barmac]

I've prepared a PR aiming to fix the flaky test causing CI to fail: #910

[nikku]

This still works as expected. The comments are a valuable addition ✔️