Fix default icon for Withings sleep sensor (#37502)

The icon for Withings sleep sensor was using `mdi:bed` (which is correct for MDI v5.0.45 and later). However Home Assistant still uses an older version of Material Design Icons (4.9.95), so this `mdi:bed` icon was not displaying at all.  It should be`mdi:hotel` instead, which you can see here: https://cdn.materialdesignicons.com/4.9.95/