fix(useMutation): add Override to override mutate and return correct union type

Author: raoufswe

src/react/types.ts

@@ -124,17 +124,16 @@ export type UseBaseMutationResult<
   TError = unknown,
   TVariables = unknown,
   TContext = unknown
-> = Exclude<
+> = Override<
   MutationObserverResult<TData, TError, TVariables, TContext>,
-  'mutate'
-> & {
-  mutate: UseMutateFunction<TData, TError, TVariables, TContext>
-  mutateAsync: UseMutateAsyncFunction<TData, TError, TVariables, TContext>
-}
+  { mutate: UseMutateFunction<TData, TError, TVariables, TContext> }
+> & { mutateAsync: UseMutateAsyncFunction<TData, TError, TVariables, TContext> }
 
 export type UseMutationResult<
   TData = unknown,
   TError = unknown,
   TVariables = unknown,
   TContext = unknown
 > = UseBaseMutationResult<TData, TError, TVariables, TContext>
+
+type Override<A, B> = { [K in keyof A]: K extends keyof B ? B[K] : A[K] }