Add support for creating specs for React components that are exported as default

[astone123]

For the Create from React Component feature, we're using react-docgen to parse files and return any React components that are defined and exported. Unfortunately, this tool does not tell us whether a component is a named export or the default export.

This is a problem because when we create the spec file, we need to either import the component by name (import { MyComponent } from 'file') or by default (import DefaultComponent from 'file'). Right now, the spec template assumes that the component is a named export, so the spec will fail to run if it is exported by default.

There is also an edge-case with export { Foo as Bar } aliasing where react-docgen returns information about Foo but import {Foo} from '...' would not work correctly.

We should be able to use a custom resolver with react-docgen to add information to the response about whether each component is a named or default export. We should then be able to use this information to craft the correct import statement in the generated spec file.

[cypress-bot]

The code for this is done in cypress-io/cypress#24954, but has yet to be released.
We'll update this issue and reference the changelog when it's released.