message: Fix usage of keycloak session
diff: import React from 'react'
  -import { useTranslation } from 'next-i18next'
  -
  import { ThemeProvider } from '@mui/styles'
  +import { useSession } from 'next-auth/react'
  +import { useTranslation } from 'next-i18next'
  import { Grid, Typography } from '@mui/material'
  import theme from 'common/theme'
  -import { useSession } from 'common/util/useSession'
  import Subtitle from '../helpers/Subtitle'
  import Link from 'components/common/Link'
  @@ -17,7 +16,7 @@ const greetingStyles = {
  export default function Greeting() {
  const { t } = useTranslation('irregularity-report')
  - const { session } = useSession()
  + const { data: session } = useSession()
  return (
  <ThemeProvider theme={theme}>
  @@ -29,7 +28,9 @@ export default function Greeting() {
  <Typography variant="h6" sx={greetingStyles}>
  {t('steps.greeting.welcome')}{' '}
  {session &&
  - (session.preferred_username ? session.preferred_username : session.given_name)}
  + (session?.user?.preferred_username
  + ? session.user.preferred_username
  + : session.user.given_name)}
  </Typography>
  </Grid>
  <Grid container item spacing={3}>
  