Correctly handle Input::Message when calling msg_sender()

[bitzoic]

Description

When the input type was of Input::Message and the msg_sender() function was called, it would revert. It now properly handle Input::Message.

Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
  • If my change requires substantial documentation changes, I have requested support from the DevRel team
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[kayagokalp]

Pushed 4b49224 as #6236 is merged and CI should be green after that.