PHP8 compatibility

Observed the following fatal when running under PHP8. This causes a failure in the QR code generation and display in the CMS. Reverting back to PHP7.4 fixes the issue.

[10-May-2022 12:16:19 UTC] PHP Fatal error:  Uncaught TypeError: count(): Argument #1 ($value) must be of type Countable|array, bool given in /nas/content/live/hmmdev/wp-content/plugins/google-authenticator/google-authenticator.php:711
Stack trace:
#0 /nas/content/live/hmmdev/wp-content/plugins/google-authenticator/google-authenticator.php(365): GoogleAuthenticator->profile_personal_options(Array)
#1 /nas/content/live/hmmdev/wp-includes/class-wp-hook.php(307): GoogleAuthenticator->user_setup_page('')
#2 /nas/content/live/hmmdev/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters('', Array)
#3 /nas/content/live/hmmdev/wp-includes/plugin.php(474): WP_Hook->do_action(Array)
#4 /nas/content/live/hmmdev/wp-admin/admin.php(259): do_action('admin_page_goog...')
#5 {main}
  thrown in /nas/content/live/hmmdev/wp-content/plugins/google-authenticator/google-authenticator.php on line 711