Remove eon from AnyVote

[Jimbo4350]

Changelog

- description: |
    Remove eon from `AnyVote`
  type:
  - breaking       
  - refactoring    
  projects:
  - cardano-api

Context

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Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[carbolymer]

Could we avoid matching on every era? This just adds a boilerplate to maintain. Why not

let era = either (const Nothing) pure $ sbeToEra sbe
maybe id (\era' -> obtainEraCommonConstraints era' $ overwrite votingProcedures) era