Setting a huge height with !important caused these viewers to be
much larger than their container.

This fixes the height issue with the initial render.

We now only support Rails 7, and no longer build the test app
without javascript, so these Hotwire libraries will always be
installed automatically and don't need special handling.

Both `yarn link` and `npm link` do not install the dependencies
of the linked package. This means that things like leaflet are
not actually available in a dev/test context when building the
frontend, even though they would be in a production context
where the frontend package is installed normally.

This PR fixes the situation by borrowing the same approach as
blacklight, which instead adds the package with `yarn add` pointing
to the parent directory. This way, its dependencies will be installed
at the correct level and available for building with Vite.

Add ability to run template.rb with a branch