[MM-52841] : Migrate "components/admin_console/set_by_env.jsx" to Typescript (#23451)

webapp/channels/src/components/admin_console/set_by_env.tsx

@@ -4,7 +4,7 @@
 import React from 'react';
 import {FormattedMessage} from 'react-intl';
 
-export default function SetByEnv() {
+export default function SetByEnv(): JSX.Element {
     return (
         <div className='alert alert-warning'>
             <FormattedMessage