Turn on multi-project in web if user has feature flag

[franknoirot]

Enable all the project-based features that were turned off just before "multifile on web" rollout, if the user has our gating feature flag. I believe this will basically replace all remaining isDesktop checks with isDesktop || hasCloudStorageFlag.

[pierremtb]

Linking this existing work from @iterion @franknoirot #11083