fix: isequal: remove dep and replace with utility function derivation

[dkilgore-eightfold]

SUMMARY:

• Removes @ngard/tiny-isequal dependency
• Replace with a local, transcribed utility function
• Removes old hacked type definition (my bad)

JIRA TASK (Eightfold Employees Only):

ENG-90064

CHANGE TYPE:

• [x] Bugfix Pull Request
• [ ] Feature Pull Request

TEST COVERAGE:

• [ ] Tests for this change already exist
• [x] I have added unittests for this change

TEST PLAN:

Pull the PR branch and run yarn and yarn storybook. Test the DatePicker stories behave as expected.

[codesandbox-ci[bot]]

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