Fix progressive calls: remove options in subsequent calls

[KSDaemon]

Description, Motivation and Context

The WAMP Spec defines that all options except progress should be removed from subsequent progressive call messages on the Caller and/or Dealer sides. This PR syncs nexus logic with the spec.

Refs wamp-proto/wamp-proto#511
See WAMP Spec section for details.

What kind of change does this PR introduce?

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• I have added tests to cover my changes.
• Overall test coverage is not decreased.
• All new and existing tests passed.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.

[KSDaemon]

@gammazero gentle ping here....

[KSDaemon]

Okay... I'll merge it.