Implements a semi-working version of flash photo capture for Android.
This isn't properly implemented because a proper implementation requires a fully custom precapture sequence that enables the torch, then waits for AE/AF to adjust, lock AE/AF, then capture with a single torch burst, and then turn the torch off again. This is quite complex, that's why the feature request #1890 is marked at $3,000.
For now, this is a simple flash burst which _sometimes works_, _sometimes not_ - highly depends on the device.
If anyone wants true working flash capture, sponsor in #1890.
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