Support Emoji in WiFi SSID

[techninja]

Yup, just like it says on the tin! I happen to have a single emoji in my WiFi SSID and as soon as this is added, validation fails for the field, likely thanks to its very character restrictive pattern match: ^[\x00-\x7F\u0080-\uFFFF]{2,32}$

I can of course simply remove this pattern from the field in dev tools and the form submits just fine, but we get an initialization failure after it flashes and attempts to boot, making me think there's some UTF-8 unsafe string handling somewhere for config? Unsure.

Error as reported in the web flash console:

WILLOW/MAIN: failed to get PSK from NVS namespace WIFI: ESP_OK

FWIW, I run a number of other ESP devices on the same wifi, and have even web flashed other projects with emoji wifi so it isn't an issue with hardware support.

[techninja]

Just tried it on the preview flasher, slightly different output:

I (1149) spiram: Reserving pool of 16K of internal memory for DMA/internal allocations
I (08:40:48.989) WILLOW/MAIN: Starting up! Please wait...
I (08:40:49.074) WILLOW/MAIN: SPIFFS mounted
I (08:40:49.074) WILLOW/CONFIG: opening /spiffs/user/config/willow.json
E (08:40:49.136) WILLOW/CONFIG: failed to open /spiffs/user/config/willow.json
I (08:40:51.621) WILLOW/NETWORK: initializing SNTP client
I (02:40:51.622) WILLOW/NETWORK: Using configured SNTP server 'pool.ntp.org'
E (02:40:51.628) WILLOW/MAIN: failed to get PSK from NVS namespace WIFI: ESP_OK

I guess more verbose debugging before shows the failed JSON open. I guess it's not parsable because of UTF-8 decoding/encoding hiccup? If there's a standard for inline escape char encoding that would support this that could be a workaround.