feat(FilterCheckboxDropdown): create accessible filter checkbox dropdown component

[ksharma-c-eightfold]

SUMMARY:

• Created a new accessible filter checkbox dropdown component.
• This is created as an expandable buttons with checkboxes rather than dropdowns.
• It does not contain aria-haspopup & role=combobox attributes from the expandable elements.
• Also we removed the role="option" and role="listbox" roles from the checkboxes.
• As well as added Fieldset and legend for the checkbox.

GITHUB ISSUE (Open Source Contributors)

JIRA TASK (Eightfold Employees Only):

https://eightfoldai.atlassian.net/browse/ENG-167512

CHANGE TYPE:

• Bugfix Pull Request
• Feature Pull Request

TEST COVERAGE:

• Tests for this change already exist
• I have added unittests for this change

TEST PLAN:

[codesandbox-ci]

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