fix: feature page qa fixes

[brainbicycle]

This PR resolves []

cc @artsy/diamond-devs

Description

• handle case when feature is null (don't show Unable to Load)
• removes hairline above video sets
• fixes issue in feature description causing bolded and italicized text not to match text styles
• downsize text sizes and change colors to match force more closely

Follow-ups

• having trouble with android setup, will do more testing there when I can

Platform	Before	After
Android
iOS	feature-before-low.mov	feature-after-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

• qa fixes for the feature page - brian

iOS user-facing changes

Android user-facing changes

Dev changes

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[ArtsyOpenSource]

This PR contains the following changes:

• Cross-platform user-facing changes (qa fixes for the feature page - brian - brainbicycle)

Generated by 🚫 dangerJS against 3c0ed0a

[anandaroop]

Much nicer, thanks 🙏🏽