feat: Added checkboxUnselectedColor and checkboxDisabledStyle to checkboxControls Object

[azeezat]

Description

Added checkboxUnselectedColor and checkboxDisabledStyle to checkboxControls Object

checkboxUnselectedColor allows user to change the unselected checkbox background from white to another color.
checkboxDisabledStyle allows you to style a checkbox that has been disabled.

Fixes #67 #82

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

  checkboxControls={{
              checkboxDisabledStyle: {
                borderColor: 'red',
                backgroundColor: 'red',
              },
              checkboxUnselectedColor: 'black',
            }}

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules