Fix frontend bugs

An api path was missing a slash and a save button did not redirect back
to the previous location

frontend/src/routes/guest/register/index.tsx

@@ -69,7 +69,7 @@ export default function GuestRegister() {
 
   const guestContactInfo = async () => {
     try {
-      const response = await fetch('/api/ui/v1/invited')
+      const response = await fetch('/api/ui/v1/invited/')
 
       if (response.ok) {
         response.json().then((jsonResponse) => {

frontend/src/routes/sponsor/guest/newGuestRole/index.tsx

@@ -20,7 +20,7 @@ import { Guest } from 'interfaces'
 import { useState } from 'react'
 import { Controller, useForm } from 'react-hook-form'
 import { useTranslation } from 'react-i18next'
-import { Link, useParams } from 'react-router-dom'
+import { Link, useHistory, useParams } from 'react-router-dom'
 import SponsorInfoButtons from 'routes/components/sponsorInfoButtons'
 import { submitJsonOpts } from 'utils'
 
@@ -103,8 +103,10 @@ function NewGuestRole({ guest }: NewGuestRoleProps) {
   } = useForm<AddRoleFormData>()
 
   const { pid } = useParams<GuestInfoParams>()
+  const history = useHistory()
   const onSubmit = handleSubmit(() => {
     postRole(getValues(), pid)
+    history.push(`/sponsor/guest/${pid}`)
   })
 
   const ous = useOus()