chore(deps): bump Microsoft.Extensions.Hosting.Abstractions from 6.0.0 to 7.0.0 in /src/fdc3/dotnet/DesktopAgent/src/DesktopAgent

chore(deps): bump Microsoft.Extensions.Hosting.Abstractions from 6.0.0 to 7.0.0 in /src/fdc3/dotnet/DesktopAgent/src/DesktopAgent #21