fix(richtext-lexical): Blocks: z-index issue, e.g. select field dropdown in blocks hidden behind blocks below, or slash menu inside nested editor hidden behind blocks below

test/fields/collections/Lexical/blocks.ts

@@ -113,6 +113,7 @@ export const SubBlockBlock: Block = {
             },
           ],
         },
+        SelectFieldBlock,
       ],
     },
   ],

test/fields/lexical.e2e.spec.ts

@@ -300,7 +300,7 @@ describe('lexical', () => {
       const textNode1: SerializedTextNode = paragraphNodeInBlockNodeRichText.children[0]
       const boldNode: SerializedTextNode = paragraphNodeInBlockNodeRichText.children[1]
 
-      expect(textNode1.text).toBe('Some text below ')
+      expect(textNode1.text).toBe('Some text below r')
       expect(textNode1.format).toBe(0)
 
       expect(boldNode.text).toBe('elationship node 1')