feat(richtext-lexical): more lenient MDX JSON object parser that allows unquoted property keys

[AlessioGr]

Previously, the following MDX could not be parsed by lexical:

<RestExamples
  data={[
    {
      operation: "Find"
    }
]}

Instead, it had to be converted into valid JSON:

<RestExamples
  data={[
    {
      "operation": "Find"
    }
]}

This PR permits using the first example, as it swaps out JSON.parse with them ore lenient json5 package parser

[github-actions]

🚀 This is included in version v3.12.0