Tools/MMaps: Fix strange paths in Blackfathom Deeps

Increase the agent height by x2 to reduce the chance of having underground mmap layers wrongly picked by recast.

(cherry picked from commit 3b0a89a2ea)

src/tools/mmaps_generator/MapBuilder.cpp

@@ -997,8 +997,14 @@ namespace MMAP
         {
             // Blade's Edge Arena
             case 562:
+                // This allows to walk on the ropes to the pillars
                 config.walkableRadius = 0;
                 break;
+            // Blackfathom Deeps
+            case 48:
+                // Reduce the chance to have underground levels
+                config.ch *= 2;
+                break;
             default:
                 break;
         }