Hovering "handsontable" cell type header handles won't throw an error

[wszymanski]

Context

It seems that mouseover event attached to HOT's root element is executed twice when we have HOT in HOT element. One event is called for the main instance and the second one for editor being a Handsontable. Callback in one from the cases is trying to overwrite private variables (related to main instance) which shouldn't be touched.

HOT in HOT will handle it's callback by its own anyway. Thus, this PR adds an extra conditional which checks whether callback should be executed.

How has this been tested?

Tested case from the issue, another from #10359, HOT with table in a column header, checked whether ContextMenu work properly.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature or improvement (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Additional language file or change to the existing one (translations)

Related issue(s):

1. [8.0.0+] Hovering handsontable cell type header handles throws an error #9317
2. Hovering embedded table header cell crashes the app #10359

Affected project(s):

• handsontable
• @handsontable/angular
• @handsontable/react
• @handsontable/vue
• @handsontable/vue3

Checklist:

• I have reviewed the guidelines about Contributing to Handsontable and I confirm that my code follows the code style of this project.
• My change requires a change to the documentation.

[github-actions]

Launch the local version of documentation by running:

npm run docs:review 2ec84e655d2733b3de6c71218c9ece31bd12a441