chore(formlist): remove /api/v1/formlist endpoint DEV-1376

[rajpatel24]

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📣 Summary

Removed /api/v1/formlist endpoint.

[Guitlle]

Remove the related tests and obsolete classes too

[rajpatel24]

Remove the related tests and obsolete classes too

@Guitlle The same viewset class, XFormListApi, is being used for the OpenRosa formList endpoint. The tests are also using this OpenRosa endpoint, which is why I left those unchanged.