chore(DIA-629): retire AREnableNewTermsAndConditions

[iskounen]

This PR resolves DIA-629

Description

This PR deprecates AREnableNewTermsAndConditions by removing the feature flag from components where it was used.

See: artsy/echo#673

PR Checklist

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

• Deprecated AREnableNewTermsAndConditions feature flag

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