Improve SaveButton Redux tests with modern store patterns

[zetter-rpf]

Summary

• reduce repeated setup in SaveButton.test.js and align it with a shared test utility
• migrate SaveButton.test.js from redux-mock-store to a real Redux Toolkit configureStore instance using rootReducer
• replace dispatched-action-list assertions with reducer outcome assertions (editor.saveTriggered)
• add reusable renderWithProviders utility in src/utils/renderWithProviders.js
• remove local renderSaveButton wrapper and call renderWithProviders directly in setup blocks
• rename local fixture objects from initialState to preloadedState and use object shorthand
• fix lint warnings by removing unused store bindings in setup blocks that only assert rendered class names

Why this is an improvement

• follows Redux’s recommended integration-style testing with a real store
• verifies observable state outcomes instead of mock action internals
• reduces Redux test boilerplate and standardizes setup around one shared helper API
• uses Redux Toolkit terminology (preloadedState) for clearer intent
• keeps lint output clean and avoids warning noise in CI and local runs

Testing

• CI=true yarn test --runInBand --runTestsByPath src/components/SaveButton/SaveButton.test.js
• yarn lint

  

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