Fix water infrastructure accounting when building docks

See: https://github.com/OpenTTD/OpenTTD/issues/10419

src/station_cmd.cpp

@@ -3061,8 +3061,8 @@ CommandCost CmdBuildDock(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 		st->rect.BeforeAddRect(dock_area.tile, dock_area.w, dock_area.h, StationRect::ADD_TRY);
 
 		/* If the water part of the dock is on a canal, update infrastructure counts.
-		 * This is needed as we've unconditionally cleared that tile before. */
-		if (wc == WATER_CLASS_CANAL) {
+		 * This is needed as we've cleared that tile before. */
+		if (wc == WATER_CLASS_CANAL && !(HasTileWaterClass(flat_tile) && GetWaterClass(flat_tile) == WATER_CLASS_CANAL && IsTileOwner(flat_tile, _current_company))) {
 			Company::Get(st->owner)->infrastructure.water++;
 		}
 		Company::Get(st->owner)->infrastructure.station += 2;