Fix: Copy-Paste-Brush with falsy mask (#2899)

* fix: don't attempt to load all possible world chunks when copy pasta brush empty clipboard

* chore: move check into ResizableClipboardBuilder

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/clipboard/ResizableClipboardBuilder.java

@@ -58,6 +58,9 @@ public class ResizableClipboardBuilder extends MemoryOptimizedHistory {
     }
 
     public Clipboard build() {
+        if (longSize() == 0) {
+            return EmptyClipboard.getInstance();
+        }
         BlockVector3 pos1 = BlockVector3.at(minX, minY, minZ);
         BlockVector3 pos2 = BlockVector3.at(maxX, maxY, maxZ);
         CuboidRegion region = new CuboidRegion(pos1, pos2);