Perform dead code analysis with Knip (#2575)

* Install Knip

* Clarify an import that was confusing Knip

* Fix issues detected by Knip

Including cleaning up some unused code and dependencies, using a React hook that we unintentionally stopped using, and also adding some previously undeclared dependencies.

* Run dead code analysis in lint script and CI

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Co-authored-by: Timo <toger5@hotmail.de>

src/useLocalStorage.ts

@@ -50,9 +50,6 @@ export const useLocalStorage = (
   ];
 };
 
-export const getLocalStorageItem = (key: string): LocalStorageItem =>
-  localStorage.getItem(key);
-
 export const setLocalStorageItem = (key: string, value: string): void => {
   localStorage.setItem(key, value);
   localStorageBus.emit(key, value);