Implement html5-qrcode Torch/Flashlight feature in frappe.ui.Scanner

Is your feature request related to a problem? Please describe. Many users on manufacturing shopfloors perform their work throughout the whole plant, including areas with lower levels of lighting (think cold rooms, storage areas etc). Their work includes scanning product barcodes using the Barcode Scanner on Data fields with Options set to Barcode. When there is not enough light for the device's camera, the barcode scanner doesn't work.

Describe the solution you'd like To add a "Torch" button on the frappe.ui.Scanner prompt, that controls the Torch/Flashlight if supported.

html5-qrcode, the library that is used by frappe.ui.Scanner, has a feature of turning on the device's Torch/Flashlight (if it is supported) - see mebjas/html5-qrcode/issues/129.

Describe alternatives you've considered

• Attempted to turn on the device's Torch/Flashlight while the frappe.ui.Scanner prompt is open, but the Torch/Flashlight can not be controlled from the device's setting shortcuts/status bar if an app is using the camera (iOS and Android)

Additional context

An example: