Add WiFi/BT toggle for screenless devices

[lkosson]

With this change, long-pressing a button on headless devices (such as Seeed Xiao ESP32) toggles between Wi-Fi and Bluetooth.

The goal is to provide an easy way to recover from misconfigured or outdated Wi-Fi settings, when serial USB connection to the device is not available. ESP32-based modules can't have BT and Wi-Fi enabled at the same time, and require a reboot to switch between them. This PR binds previously unused (on devices without screen) long-press event to perform such switch.

🤝 Attestations

• I have tested that my proposed changes behave as described.
• I have tested that my proposed changes do not cause any obvious regressions on the following devices:
  • Heltec (Lora32) V3
  • LilyGo T-Deck
  • LilyGo T-Beam
  • RAK WisBlock 4631
  • Seeed Studio T-1000E tracker card
  • Other (Seeed Xiao ESP32-S3)

[fifieldt]

I'll let people more familiar with the button code comment, however one item: you probably want to limit this to ESP32 devices. It doesn't have meaning for eg NRF52, which don't have wifi.