Remove major code smells from the source code

[budnix]

Context

The PR removes all major code smells from the source code detected by the SonarCloud tool. Additionally, the PR fixes regular expression (marked as "risk") responsible for detecting numeric values. The expression causes performance degradation when an empty string is passed.

Test code snippet:
Handsontable.helper.isNumeric(' '.repeat(100000));

Results:

	PR	9.0.2
isNumeric helper	~0.37ms	~7500ms

Working demo

PR	9.0.2
https://jsfiddle.net/budnix/mthor6w1/1/	https://jsfiddle.net/budnix/uo9stj45/1/

I analyzed this branch after my changes and the results can be found here https://sonarcloud.io/summary/new_code?id=handsontable_handsontable&pullRequest=8742.

How has this been tested?

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. fixes Fix RegExp vulnerability and clean up major code smells #8752

Affected project(s):

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

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
• My change requires a change to the documentation.

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