refactor: Export reducers from dashboard package (#1522)

* Exported reducers defined in `dashboard` package
* Removed unused reducers from `dashboard-core-plugins` and `redux`
packages

* Resolves #1487

Author: georgecwan

packages/dashboard-core-plugins/src/redux/actionTypes.ts

@@ -1,10 +1,2 @@
-import { reducerRegistry } from '@deephaven/redux';
-import reducers from './reducers';
-
-Object.entries(reducers).map(([name, reducer]) =>
-  reducerRegistry.register(name, reducer)
-);
-
 export * from './actions';
-export * from './actionTypes';
 export * from './selectors';

packages/dashboard-core-plugins/src/redux/index.ts

@@ -5,6 +5,7 @@ Object.entries(reducers).map(([name, reducer]) =>
   reducerRegistry.register(name, reducer)
 );
 
+export { reducers };
 export * from './actions';
 export * from './actionTypes';
 export * from './selectors';