Add option to enable auto data switching toggle

[TannerHarman]

Is your feature request related to a problem? Please describe.

On older OnePlus devices, they are missing the Auto Data Switching toggle in the NA ROM. Though it's available for the Indian ROM.

Describe the solution you'd like
If possible, I'd love for an option to be added that allows a toggle to enable that setting.

Describe alternatives you've considered
I've flashed the IN ROM onto my phone, and it works, but I lose out on other carrier features (like wifi calling) that are offered with the NA ROM.

Additional context
Is there anything I can do to help get this moving? I'm familiar with web dev, never done much with coding apps before. Previous experience rooting, flashing custom Roms, etc...