fix: colour from colour picker not being updated (#7584)

* fix: colour from colour picker not being updated

* chore: clarify what code is doing

core/field_colour.ts

@@ -246,12 +246,9 @@ export class FieldColour extends Field<string> {
 
     const block = this.getSourceBlock() as BlockSvg | null;
     if (!block) throw new UnattachedFieldError();
-    // In general, do *not* let fields control the color of blocks. Having the
-    // field control the color is unexpected, and could have performance
-    // impacts.
-    // Whenever we render, the field may no longer be a full-block-field so
-    // we need to update the colour.
-    if (this.getConstants()!.FIELD_COLOUR_FULL_BLOCK) block.applyColour();
+    // Calling applyColour updates the UI (full-block vs non-full-block) for the
+    // colour field, and the colour of the field/block.
+    block.applyColour();
   }
 
   /**