chore: use type imports / avoid unnecessary API type export (#28088)

apps/docs/types/api.d.ts

@@ -1,4 +0,0 @@
-/**
- * Avoid importing this file and import the types directly from api-types
- */
-export * from 'api-types'

apps/docs/types/next.ts

@@ -1,6 +1,6 @@
-import { NextPage } from 'next'
-import { AppProps } from 'next/app'
-import { ReactElement, ReactNode } from 'react'
+import type { NextPage } from 'next'
+import type { AppProps } from 'next/app'
+import type { ReactElement, ReactNode } from 'react'
 
 export type AppPropsWithLayout = AppProps & {
   Component: NextPageWithLayout