Good question. Even though Panasonic may have built the lens for DJI, would they service it? Same could be said of the DJI X7 lenses as well (Being Sigma or Panny built.). Dunno.
Could be why DJI included that elastic band - that I never use (ahem!) - to cover the seams in the lens barrel too.
I don't think you'll be able to clean it yourself.
If the debris is on the lens elements and you can't dislodge it by tapping the lens, then it would need servicing by the manufacturer, so DJI or Panasonic. They have the tools and knowledge to disassemble the lens, clean it and put it back together. I've partly dismantled a Canon EF lens repair the lens mount after dropping it... looking at the inside of it I wouldn't want to service the whole thing
If it's not causing any issues on your images, then I wouldn't worry about it. I've a couple of lenses for dslrs which have dust visible on the internal elements, but which don't cause any problems with the images.