Metadata not generated correctly for Typescript components

With TypeScript components, the metadata.json file is not generated correctly in cases where there is a union with a boolean.

For example,

persistence?: boolean | string | number;

The metadata.json file only includes the string and number but not the boolean.

 "persistence": {
        "description": "Used to allow user interactions in this component to be persisted when\nthe component - or the page - is refreshed. If `persisted` is truthy and\nhasn't changed from its previous value, a `value` that the user has\nchanged while using the app will keep that change, as long as\nthe new `value` also matches what was given originally.\nUsed in conjunction with `persistence_type`.",
        "required": false,
        "type": {
          "name": "union",
          "value": [
            {
              "name": "string",
              "raw": "string"
            },
            {
              "name": "number",
              "raw": "number"
            }
          ],
          "raw": "string | number | boolean"
        }
      },

The docstrings are not generated correctly:

Also, setting the persistence=True on the component generates this warning in the console:

Start by tracing how metadata.json is generated for TypeScript component props, using the persistence?: boolean | string | number example to reproduce the issue. Done means the generated union retains boolean, the component docstrings reflect it, and setting persistence=True no longer produces the reported warning.