chore: cleanup sale ff

[brainbicycle]

This PR resolves []

Description

This feature flag has been out a while now and we should be okay to remove. Can remove quite a bit of legacy code with this gone.

UX is the same as previous.

Platform	Before	After
Android		android-sale-low.mov
iOS		ios-sale-low.mov

PR Checklist

• I have tested my changes on the following platforms:
  • Android.
  • iOS.
• I hid my changes behind a feature flag, or they don't need one.
• I have included screenshots or videos at least on Android, or I have not changed the UI.
• I have added tests, or my changes don't require any.
• I added an app state migration, or my changes do not require one.
• I have documented any follow-up work that this PR will require, or it does not require any.
• I have added a changelog entry below, or my changes do not require one.

To the reviewers 👀

• I would like at least one of the reviewers to run this PR on the simulator or device.

Changelog updates

Changelog updates

Cross-platform user-facing changes

iOS user-facing changes

Android user-facing changes

Dev changes

• remove old sale artworks connection feature flag and associated code - brian

Need help with something? Have a look at our docs, or get in touch with us.

[araujobarret]

Looks good! Idk if we still create PRs to Echo to mark when the FF was retired, but this is enough on Eigen's side, thanks for pushing it 👍

[ArtsyOpenSource]

This PR contains the following changes:

• Dev changes (remove old sale artworks connection feature flag and associated code - brian - brainbicycle)

Generated by 🚫 dangerJS against a366265

[brainbicycle]

Looks good! Idk if we still create PRs to Echo to mark when the FF was retired, but this is enough on Eigen's side, thanks for pushing it 👍

i think we might as well keep it up, would be nice to go through and mark old ones as retired at some point, and then we might actually be able to shrink this json at some point 🙏

artsy/echo#923