Fix custom borders overlap problem

[adrianspdev]

Context

This PR includes fixes for the issue with overlapping borders. After the changes, all borders should be placed inside the table.

Classic
Before:

After:

Main
Before:

After:

Horizon
Before:

After:

How has this been tested?

Locally and covered by new visual test case

Types of changes

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Related issue(s):

1. https://github.com/handsontable/dev-handsontable/issues/638

Affected project(s):

• handsontable

Checklist:

• I have reviewed the guidelines about Contributing to Handsontable and I confirm that my code follows the code style of this project.
• I have signed the Contributor License Agreement

[codesandbox-ci]

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Latest deployment of this branch, based on commit 624d8e7:

Sandbox	Source
handsontable-pr-javascript-demo	Configuration
handsontable-ts-demo	Configuration
handsontable-pr-react-demo	Configuration

[budnix]

Looks much better 👍