Added callback to fluxible rehydrate function definition (#35229)

* Added callback to fluxible rehydrate function definition

* Fixed the type of the rehydrate callback property in fluxible

* Made callback function optional in fluxible's rehydrate

* Fixed callback parameter for rehydrate in fluxible

types/fluxible/index.d.ts

@@ -90,7 +90,7 @@ export class Fluxible {
      * @param callback
      * @async Rehydration may require more asset loading or async IO calls
      */
-    rehydrate(state: any): void;
+    rehydrate(state: any, callback?: (err: Error, context: FluxibleContext) => void): void;
 }
 
 /**