A AAA battery shouldn't cause an issue because it should be smaller than the slide rollers. You can try to park with the slide side slightly elevated and see if the battery can be fished out using a wire clothes hanger.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054
We found a hinge, a cabinet door strut, a kitchen drawer latch, about a dozen screws and a pound of sawdust under the slide of our 29M. I don't think a AAA battery will do any damage. A used a wooden yardstick to clean everything out.