docs: fix import of defineMiddleware (medusajs#11293)

Author: shahednasser

www/apps/book/app/learn/fundamentals/api-routes/middlewares/page.mdx

@@ -27,7 +27,7 @@ Middlewares are defined in the special file `src/api/middlewares.ts`. Use the `d
 For example:
 
 ```ts title="src/api/middlewares.ts"
-import type { 
+import { 
   defineMiddlewares,
   MedusaNextFunction, 
   MedusaRequest, 
@@ -118,7 +118,7 @@ For example:
 export const pathParamHighlights = [["11", ":id", "Indicates that the API route accepts an `id` path parameter."]]
 
 ```ts title="src/api/middlewares.ts" collapsibleLines="1-7" expandMoreLabel="Show Imports" highlights={pathParamHighlights}
-import type { 
+import { 
   MedusaNextFunction, 
   MedusaRequest, 
   MedusaResponse, 
@@ -150,7 +150,7 @@ For example:
 export const highlights = [["12", "method", "Apply the middleware only on `POST` requests"]]
 
 ```ts title="src/api/middlewares.ts" highlights={highlights} collapsibleLines="1-7" expandButtonLabel="Show Imports"
-import type { 
+import { 
   MedusaNextFunction, 
   MedusaRequest, 
   MedusaResponse, 
@@ -183,7 +183,7 @@ A middleware whose `matcher` pattern doesn't end with a backslash won't be appli
 For example, consider you have the following middleware:
 
 ```ts collapsibleLines="1-7" expandMoreLabel="Show Imports"
-import type { 
+import { 
   MedusaNextFunction, 
   MedusaRequest, 
   MedusaResponse, 
@@ -214,4 +214,4 @@ If you send a request to `http://localhost:9000/custom`, the middleware will run
 
 However, if you send a request to `http://localhost:9000/custom/`, the middleware won't run.
 
-In general, avoid adding trailing backslashes when sending requests to API routes.
+In general, avoid adding trailing backslashes when sending requests to API routes.