Allow a custom equals parameter for observable collections

[amondnet]

Describe the changes proposed in this Pull Request.

Allow a custom equals parameter for observable collections, like observable stream, observable and computed .

https://github.com/mobxjs/mobx.dart/pull/771 https://github.com/mobxjs/mobx.dart/pull/482

If the PR fixes a specific issue, reference the issue with Fixes #.

---

Pull Request Checklist

• [ ] If the changes are being made to code, ensure the version in pubspec.yaml is updated.
• [ ] Increment the major/minor/patch/patch-count, depending on the complexity of change
• [ ] Add the necessary unit tests to ensure the coverage does not drop
• [ ] Update the Changelog to include all changes made in this PR, organized by version
• [ ] Run the melos run set_version command from the root directory
• [ ] Include the necessary reviewers for the PR
• [ ] Update the docs if there are any API changes or additions to functionality

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🔨 Latest commit	d13d88d4e59d6313ab56c11dc10523aace309789

[codecov[bot]]

Codecov Report

Merging #970 (d13d88d) into main (d14a27e) will decrease coverage by 0.62%. Report is 3 commits behind head on main. The diff coverage is 83.33%.

Additional details and impacted files

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