Allow using additional parameters in page provider for select2 suggestions

This issue is about getting back the feature added to the old document suggestion widget, described in NXP-11014.

This feature could be implemented in the context of the operation by:

• restoring a Seam context if there is none, thanks to a parameter sent when calling the operation, and holding the conversation id
• resolving the potential additional parameters in this context
• removing the Seam context