Do not try to disable Grammarly in Slate

[e1himself]

Description

Stop trying to disable Grammarly extension from working in Slate editors.

Issue
Fixes: #4124

Example

Context

The Grammarly extension is not causing DOM issues anymore, as they have reworked their highlighting logic:
https://www.grammarly.com/blog/engineering/making-grammarly-feel-native-on-every-website/

Also the data-gramm attribute (introduced in #733) is no longer working actually (see #4124), as the Grammarly team changed the name.

Though applying Grammarly suggestions is still broken: #4579 (but it does not break the editor, so it may be fine).

Checks

• The new code matches the existing patterns and styles.
• The tests pass with yarn test.
• The linter passes with yarn lint. (Fix errors with yarn fix.)
• The relevant examples still work. (Run examples with yarn start.)
• You've added a changeset if changing functionality. (Add one with yarn changeset add.)

[changeset-bot]

🦋 Changeset detected

Latest commit: 6ea4ae6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
slate-react	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[dylans]

Thanks, it does look Grammarly has resolved the issues with their approach.