Revert "chore: remove duplicated code"

[RafaelGSS]

Reverts #917

This is breaking security release proposal creation.

As I said to @aduh95 via Slack:

Basically, you are calling LandingSession method using this as CherryPick
and some LandingSession methods expect this to be LandingSession to read this.signGpg & this.upstream

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.15%. Comparing base (a7d21f7) to head (affd8ed).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #952   +/-   ##
=======================================
  Coverage   80.15%   80.15%           
=======================================
  Files          39       39           
  Lines        4635     4635           
=======================================
  Hits         3715     3715           
  Misses        920      920           

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[RafaelGSS]

Should be fixed by #953