fix: dragging blocks by shadows to delete (#8138)

* Revert "fix: dragging shadow blocks (#7992)"

This reverts commit c0e6e6745f.

* fix: dragging by shadow not being deletable

* fix: unselecting shadows

* fix: revert changes to select and unselect

core/block.ts

@@ -675,6 +675,17 @@ export class Block implements IASTNodeLocation {
     return block;
   }
 
+  /**
+   * Returns this block if it is a shadow block, or the first non-shadow parent.
+   *
+   * @internal
+   */
+  getFirstNonShadowBlock(): this {
+    if (!this.isShadow()) return this;
+    // We can assert the parent is non-null because shadows must have parents.
+    return this.getParent()!.getFirstNonShadowBlock();
+  }
+
   /**
    * Find all the blocks that are directly nested inside this one.
    * Includes value and statement inputs, as well as any following statement.