feat(legend): add dataset hash and localStorage persistence for legend

[FlorinSenoner]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• New core component

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

• Test A
• Test B

Test Configuration: (Browser, etc.)

Checklist

• I linted my code with ESLint and formatted it with Prettier
• I used an AI tool for a self-review
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I created a/multiple changeset(s) describing my changes succinctly
• My changes generate no new warnings
• I updated core, so I added/extended a basic example
• I updated core, so I added/extended a story showcasing my changes
• I updated core and ensured the next.js page works on Safari and Chrome

[FlorinSenoner]

review if this is needed/wanted