Make equatable_utils.dart accessible

It can sometimes be necessary to check for equality between two objects of a dynamic type. The `objectsEquals(Object? a, Object? b)` method seems ideal for this purpose.

However, this method is located in `equatable_utils.dart`, which is a private library within the equatable package and isn't exposed for public use. While it can be imported directly, this approach results in a linter warning.

I propose making the `objectsEquals` method, or the entire `equatable_utils.dart` library, publicly accessible to resolve this issue.