That is a gas shock, designed to hold the door open when open and reduce slamming. IF the end piece has come out of the shock.. I do not know how they are held in so I can't help you. Had the end piece came off the ball... That I can fix but I've never seen the failure you posted. I suspect it's a press fit.
The part is non-critical. I'd remove the screws that hold the other end. and the part that came off and play with it (myself) or take it to ye old RV store for replacement. they are not all that expensive.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times