fix: disable open keymap split editor from toolbar

[kittaakos]

Motivation

The complete support for split editor is yet to be added to IDE2. For now, this commit turns off opening the keymaps in the JSON split editor. So that it cannot get the primary IDE2 layout into an inconsistent state.

Change description

Other information

Closes #1850

Reviewer checklist

• PR addresses a single concern.
• The PR has no duplicates (please search among the Pull Requests before creating one)
• PR title and description are properly filled.
• Docs have been added / updated (for bug fixes / features)

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Akos Kitta seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}