The packngo SDK assumed that the base API URL did not end with a slash, but equinix-sdk-go assumes that it does (since it's generated from an OpenAPI spec, all API paths in equinix-sdk-go start with a slash). A trailing slash on the base API URL doesn't cause problems for equinix-sdk-go, but it can cause confusion when triaging issues.

This removes the trailing slash from the 2 places where we are configuring the base API URL. We can do this safely now because we no longer use packngo. Alternatively, we could make the base API URL configuration optional; the API URL configured here is identical to the default used by the metalv1 package in equinix-sdk-go, so we only really need to change the API URL for tests that use a mock API. That change would be more extensive so I opted for the smallest change instead.