Tweak ESP32 Wifi sanity-check message (#19257)

Marlin/src/inc/SanityCheck.h

  * Sanity check for WIFI
  */
 #if EITHER(ESP3D_WIFISUPPORT, WIFISUPPORT) && DISABLED(ARDUINO_ARCH_ESP32)
-  #error "ESP3D_WIFISUPPORT or WIFISUPPORT requires an ESP32 controller."
+  #error "ESP3D_WIFISUPPORT or WIFISUPPORT requires an ESP32 MOTHERBOARD."
 #endif
 
 /**