Re-enable MAUI tests once MAUI supports .NET 11

[rolfbjarne]

See:

a91447a

These tests don't work because MAUI doesn't load when targeting .NET 11 yet:
https://github.com/dotnet/maui/blob/21817df98dd6577f95ab548de976c5a5d0ddc797/src/Workload/Microsoft.NET.Sdk.Maui.Manifest/WorkloadManifest.in.targets#L15-L26

Once that's fixed, re-enable the disabled tests.