(interlocutory appeal where city challenged trial court's partial denial of its plea for jurisdiction, and contends underlying case should be dismissed in entirety under doctrine of sovereign immunity; appellees, property owners and operators of agribusinesses near landfill, filed suit against city for inverse condemnation alleging landfill retention ponds overflowed from heavy rains, ruined crops and destroyed structures; city claimed sovereign immunity and contended appellees failed to identify applicable waiver; appellate court held appellees' claims failed to rise to level of inverse condemnation and other claims barred by sovereign immunity; case remanded and appellees allowed to amend pleadings).