Rackspace CloudFiles is listed but not available

[v2.1.0.118_canary_2025-05-12](https://github.com/duplicati/duplicati/releases/tag/v2.1.0.118_canary_2025-05-12)

> Removed CloudFiles backend

2.1.0.119

[Remove CloudFiles backend #6242](https://github.com/duplicati/duplicati/pull/6242)
[Removed mentions of CloudFiles #6283](https://github.com/duplicati/duplicati/pull/6283)
