Allow to call Seam.Refresh safely in a non Seam Context

When reusing the same Chain in several context (ex: User action and listener), there is an issue when Seam.Refresh is called :

• it is required in Seam Context
• it fails in non Seam Context

To avoid this issue, we should make Seam.Refresh fail silently when Seam.Context is not available.

NB : we have to handle separatly the Seam.Refresh operation since we can not have a global shield for all Seam aware operations.