If Apple's Photos.app can import Leica images from a SD card to your camera roll, then Lightroom should be able to import the images. If iOS doesn't provide support for the Leica images on your device, this isn't a Lightroom issue but is an iOS/platform issue.
As a workaround, you can import into your same Lightroom account and sync your Leica photos to cloud storage if you sign into Lightroom at https://lightroom.adobe.com/ -- this is Adobe's Lightroom web app. Import using Lightroom web works best on a Mac or PC browser, especially if you want to import directly from a SD card. And you do not need the full Lightroom Desktop subscription to use the web app -- your Lightroom Mobile subscription also provides Lightroom Web access.