[FluidNC PR#1543] Fix #1542

#1 – 0x5e 于 2025-08-28

Works for me

“
Grbl 3.0 [FluidNC v3.0.x (HEAD-fa02099) (wifi) '$' for help]
> $HOSTNAME
$Hostname=fluidnc
ok
> $HOSTNAME=aaa
ok
> $HOSTNAME
$Hostname=aaa
ok
> $HOSTNAME=bbb
ok
> $HOSTNAME
$Hostname=bbb
ok
“

#2 – 0x5e 于 2025-08-29

Set empty ssid failed, which is succeed in v3.9.7.
“
Grbl 3.0 [FluidNC v3.0.x (HEAD-fa02099) (wifi) '$' for help]
> $Sta/SSID
$Sta/SSID=xxx
ok
> $Sta/SSID=
$Sta/SSID=xxx
ok
> $Sta/SSID
$Sta/SSID=xxx
ok
`

`
Grbl 3.9 [FluidNC v3.9.7 (wifi) '$' for help]
> $Sta/SSID
$Sta/SSID=xxx
ok
> $Sta/SSID=
ok
> $Sta/SSID
$Sta/SSID=
ok
“