Improved ElementUtils Code and Test Coverage

[0rigin-c0de]

The pull request introduces improvements to the ElementUtils code and enhances the test coverage. The changes include modifications to the count and find functions, as well as adjustments to the test code.

Count function: The implementation now increments the result variable only when encountering a valid element child. This change ensures that only valid element children are counted, providing more accurate results.

Find function: The condition to set the result variable has been updated. Now, the function checks if result is falsy before assigning the child value. This change ensures that only the first matching element child is assigned to result, ignoring subsequent matches.

Test code enhancements:

Added a key prop to each element in the children array to uniquely identify them during rendering and reconciliation in React.
Adjusted the forEach test case to expect only one call to the provided callback function since non-element children are skipped.
Removed the unnecessary use of jest.fn() in the count test case since the count function is a pure utility function.
Adjusted the map test case to expect only two calls to the provided callback function since non-element children are skipped.
These changes were made to improve the accuracy and reliability of the ElementUtils code and to ensure that the test cases accurately reflect the intended behavior. The enhanced test coverage ensures comprehensive testing of the modified functions and provides a more robust validation of their functionality.