Remove link to the legacy UI (apache#47078)

We are in the process of ripping out the legacy UI, so now is the time
to stop directing folks back 🎉

Author: jedcunningham

airflow/ui/.env.example

@@ -19,4 +19,3 @@
 
 
 # This is an example. You should make your own `.env.local` file for development
-VITE_LEGACY_API_URL="http://localhost:28080/home"

airflow/ui/src/layouts/Nav/Nav.tsx

@@ -17,7 +17,7 @@
  * under the License.
  */
 import { Box, Flex, VStack, Link } from "@chakra-ui/react";
-import { FiCornerUpLeft, FiDatabase, FiHome } from "react-icons/fi";
+import { FiDatabase, FiHome } from "react-icons/fi";
 
 import { useVersionServiceGetVersion } from "openapi/queries";
 import { AirflowPin } from "src/assets/AirflowPin";
@@ -56,11 +56,6 @@ export const Nav = () => {
         <AdminButton />
       </Flex>
       <Flex flexDir="column">
-        <NavButton
-          icon={<FiCornerUpLeft size="1.75rem" />}
-          title="Legacy UI"
-          to={import.meta.env.VITE_LEGACY_API_URL || "http://localhost:28080/home"}
-        />
         <DocsButton />
         <UserSettingsButton />
         <Link

airflow/ui/src/vite-env.d.ts

@@ -20,10 +20,6 @@
 
 /// <reference types="vite/client" />
 
-interface ImportMetaEnv {
-  readonly VITE_LEGACY_API_URL: string;
-}
-
 interface ImportMeta {
   readonly env: ImportMetaEnv;
 }