Wrong z-index for rich-editor heading picker

[OlliGranlund]

Describe the issue that you're seeing. Any Loom videos or screenshots usually help a lot!

I think the screenshot explains the situation well

This happens in my Banner block, here is how it is set up:

    label: "Banner",
    name: "banner",
    fields: [
        {
            type: "rich-text",
            name: "banner_body",
            label: "Banner body",
        },
        {
            type: 'image',
            label: 'Hero image',
            name: 'image',
        },
        {
            type: 'object',
            label: "Links",
            name: "links",
            list: true,
            fields: [
                {
                    label: "Title",
                    name: "title",
                    type: "string",
                },
                {
                    label: "URL",
                    name: "url",
                    type: "string",
                },
            ]
        }
    ]
};```

### Reproduction

http://localhost:4321

### Steps to reproduce

_No response_

### System Info

```shell
"dependencies": {
    "@astrojs/check": "^0.4.1",
    "@astrojs/mdx": "^2.1.1",
    "@astrojs/partytown": "^2.0.4",
    "@astrojs/rss": "^4.0.5",
    "@astrojs/sitemap": "^3.0.5",
    "@astrojs/tailwind": "^5.1.0",
    "@builder.io/qwik": "^1.4.4",
    "@qwikdev/astro": "^0.5.2",
    "@studio-freight/lenis": "^1.0.34",
    "@tinacms/cli": "^1.5.39",
    "astro": "^4.3.4",
    "autoprefixer": "^10.4.17",
    "cssnano": "^6.0.3",
    "eslint-plugin-qwik": "^1.4.4",
    "marked": "^12.0.0",
    "tailwindcss": "^3.4.1",
    "tinacms": "^1.5.28"
  },
  "devDependencies": {
    "@typescript-eslint/eslint-plugin": "^6.21.0",
    "eslint": "^8.56.0",
    "eslint-config-standard-with-typescript": "^43.0.1",
    "eslint-plugin-import": "^2.29.1",
    "eslint-plugin-n": "^16.6.2",
    "eslint-plugin-promise": "^6.1.1",
    "typescript": "^5.3.3"
  }

Validations

• [X] Follow our Code of Conduct
• [X] Read the docs.
• [X] Check that there isn't already an issue that reports the same bug.

[sebous]

I'm seeing the same issue 🙏