fix(type): allow value from Params and SearchParams to be optional

There is no way for us to know if these params is obligated or optional from the input. So it is safer to assume that they can be undefined.

Author: ngdangtu-vn

src/types.ts

@@ -23,8 +23,8 @@ declare module "solid-js/web" {
   }
 }
 
-export type Params = Record<string, string>;
-export type SearchParams = Record<string, string | string[]>;
+export type Params = Record<string, string | undefined>;
+export type SearchParams = Record<string, string | string[] | undefined>;
 
 export type SetParams = Record<
   string,