Update Linkit module from 6.0.0-beta3 to 6.0.0-beta4 and keep needed patches for CKEditor 4

Problem/Motivation

Linkit 6.0.0-beta4 was released on: 5 Mar 2023 by: mark_fullmer
https://www.drupal.org/project/linkit/releases/6.0.0-beta4

Proposed resolution

• Change drupal/linkit to 6.0.0-beta4 in the composer.josn file.
• Keep needed patches for CKEditor 4

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ Accessibility and Readability
• ✅ Code review from 1 Varbase core team member
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Update Release Notes and Update Helper on new feature change/addition
• ✅ Release varbase-9.0.12, varbase_editor-9.0.9

Varbase update type

• ✅ No Update
• ➖ Optional Update
• ➖ Forced Update
• ➖ Forced Update if Unchanged

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• Issue #3346079: Updated Linkit module from 6.0.0-beta3 to 6.0.0-beta4 and kept needed patches for CKEditor 4