fix: Get Sanitized Name

[solracsf]

Should fix the error.

{
  ...
  "app": "circles",
  "method": "GET",
  "url": "/ocs/v2.php/apps/dashboard/api/v2/widget-items?widgets%5B%5D=circles",
  "message": "Parameter \"guestName\" for route \"core.guestavatar.getavatar\" must match \"[^/]++\" (\"Projet de Fusion ARC CSEM- OS/POs\" given) to generate a corresponding URL.",
  ...
}

MariaDB [nextcloud]> SELECT display_name, sanitized_name  FROM oc_circles_circle  WHERE display_name = 'Projet de Fusion ARC CSEM- OS/POs';
+-----------------------------------+-----------------------------------+
| display_name                      | sanitized_name                    |
+-----------------------------------+-----------------------------------+
| Projet de Fusion ARC CSEM- OS/POs | Projet de Fusion ARC CSEM- OS-POs |
+-----------------------------------+-----------------------------------+
1 row in set (0.000 sec)

[solracsf]

/backport to stable31

[solracsf]

/backport to stable30