IAsyncDisposable in scoped dependencies of custom activities

[Sverre-W]

When scoped services are getting injected in custom activities, only IDiposable is currently supported for cleaning up resources of the scoped services.

If a scoped service only supports IAsyncDisposable a System.InvalidOperationException exception will be generated indicating the resource cannot be disposed. Although Microsoft recommends to always implement IDiposable if you implement IAsyncDisposable to avoid a possible memory leak, it might be nice if the scope also supports IAsyncDisposable. This is easily achievable by using CreateScopeAsync instead of CreateScope.

This is the scope that should be adapted for the injection of services in custom activities: https://github.com/elsa-workflows/elsa-core/blob/f7f340c4aea9c8f2010319f97609eac9ee5874bd/src/core/Elsa.Core/Services/Workflows/WorkflowRunner.cs#L56

When searching in the repository, there are a few other places where it would be possible to migrate to an async scope.