Add ability for method modeling panel to render multiple modelings of the same method

[koesie10]

This makes it possible for the method modeling panel to render multiple models for the same method. It does not yet add support for updating (i.e. onChange is unchanged) or adding/removing new methods. The appearance and behavior when the feature flag is disabled should be unchanged.

The best way to view this locally is using Storybook; there are 3 different scenarios in "Method Modeling/Method Modeling".

Checklist

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.

[robertbrignull]

LGTM

[robertbrignull]

Is <VSCodeButton appearance="icon"><Codicon .../></VSCodeButton> not able to do what we want here? What are the challenges that require a new button component?

I'm not against adding a new component, but I just want to verify that it is needed.

[koesie10]

Thanks, I didn't know that this prop existed. I'll switch to use this instead. Unfortunately it makes testing a bit harder (because they're not native components), but it does mean we'll have less custom components to maintain.