Add operation identifier to invocation context; allow known errors to be returned from Smoke operation

[pbthif]

Issue #, if available:

Description of changes:

• Add operation identifier to the parameters sent for invocation context initialization.
• Allow known errors to be returned as typed errors from Smoke operations even when such error is not specified in the operation's allowed errors. Clients can opt-in error types by implementing the SmokeKnownError to specify conformance of errors to known types. For now, the only type available is unrecognizedErrorFromExternalCall.

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