Feature - Separates gate for disable_new_loader_v3_deployments

[Lichtso]

Problem

#2796 (comment)

Summary of Changes

Feature Gate Issue: https://github.com/anza-xyz/feature-gate-tracker/issues/79

[mergify]

The Firedancer team maintains a line-for-line reimplementation of the
native programs, and until native programs are moved to BPF, those
implementations must exactly match their Agave counterparts.
If this PR represents a change to a native program implementation (not
tests), please include a reviewer from the Firedancer team. And please
keep refactors to a minimum.

[joncinque]

Thank you very much!

[mergify]

The Firedancer team maintains a line-for-line reimplementation of the
native programs, and until native programs are moved to BPF, those
implementations must exactly match their Agave counterparts.
If this PR represents a change to a native program implementation (not
tests), please include a reviewer from the Firedancer team. And please
keep refactors to a minimum.