function isSameTranslation( a, b ) {
	return isEqual(
		pick( a, VALID_TRANSLATION_KEYS ),
		pick( b, VALID_TRANSLATION_KEYS )
	);
}
Given two translation objects, returns true if valid translation keys match,
or false otherwise.

@param {Object} a First translation object.
@param {Object} b Second translation object.

@returns {boolean} Whether valid translation keys match.