[MNT] Tags using enums #2235

[lucifer4073]

Reference Issues/PRs

Contributes to #2235.

What does this implement/fix?

This PR replaces string values in _tags with their corresponding Enum values in the Clustering module. These changes improve maintainability and reduce errors by standardizing tag values across the module.

Key points:

• Algorithm types can now be directly referenced using the Enum class.
• Data structures and Python dependencies utilize Enum.value for consistency.
• Changes applied across all clustering submodules containing tags.
• Dependent modules will require refactoring if direct Enum usage is extended.

Does your contribution introduce a new dependency?

No

Any other comments?

This change represents a significant milestone in transitioning to Enum-based tags. Approval for this approach in the Clustering module will allow for escalation to other modules.

Some examples of usage:

_tags = {  
    "capability:multivariate": True,  
    "algorithm_type": ClusteringAlgorithmType.DISTANCE,  
}  

tags = {  
    "capability:multivariate": True,  
    "capability:multithreading": True,  
    "python_dependencies": ClusteringAlgorithmType.TSLEARN.value,  
}  

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I have added the following labels to this PR based on the title: [ $\color{#EC843A}{\textsf{maintenance}}$ ].
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[MatthewMiddlehurst]

This seems a lot clunkier that just strings at first glance, not sure I'm a fan currently.

[MatthewMiddlehurst]

I would not do this in the clustering module, it should be more integrated with the other tags stuff in aeon/utils/tags.

[lucifer4073]

Hi @MatthewMiddlehurst @chrisholder, I have made the required changes as commented.

Since I have shifted the enum_tags.py to utils module it seems to have a circular import issue for the given test case.

Test case: PR Examples / run-notebook-examples (pull_request) Failing after 7m

Error:
ImportError: cannot import name 'BASE_CLASS_REGISTER' from partially initialized module 'aeon.utils.base' (most likely due to a circular import) (/opt/hostedtoolcache/Python/3.10.15/x64/lib/python3.10/site-packages/aeon/utils/base/__init__.py)

I propose to keep it currently in the clustering module or maybe I would need some help to resolve the error.

[TonyBagnall]

I think this issue requires some discussion before progressing, as its not obvious how best to do this and the changes, whilst under the hood, are fairly significant in terms of design

[MatthewMiddlehurst]

I thought the closure above was an accident from the force push, but maybe not. Closing for now as theres no more discussion.