enhance: pass block data to enqueue method

Ref Log1x#144 and Log1x#143 

I have played about locally on this and seems we can simply pass the `$block` array to the `enqueue` method which gives access to `$block['data']['my_field_name']`.
This allowed me to conditionally enqueue assets depending on field values.

This PR needs more work like adding the argument to `Block::enqueue($data = [])` but I opened the PR just to get the ball rolling on this.
It would result in a breaking change since the signature has changed.

@Log1x - anything to add to this? Not as nice as `get_field` in the method but hey it works.

src/Block.php

@@ -279,8 +279,8 @@ public function compose()
                 'align_content' => $this->align_content,
                 'styles' => $this->styles,
                 'supports' => $this->supports,
-                'enqueue_assets' => function () {
-                    return $this->enqueue();
+                'enqueue_assets' => function ($block) {
+                    return $this->enqueue($block);
                 },
                 'render_callback' => function (
                     $block,