chore(JS): Deduplicate FeatureFlags exports

[sgaczol]

Description

This PR deduplicates featureFlags exports.

Closes https://github.com/software-mansion/react-native-screens-labs/issues/699

Changes

• remove default export from flags.ts
• update featureFlags imports

Before & after - visual documentation

N/A

Test plan

Checklist

• Included code example that can be used to test this change.
• Updated / created local changelog entries in relevant test files.
• For visual changes, included screenshots / GIFs / recordings documenting the change.
• For API changes, updated relevant public types.
• Ensured that CI passes

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[t0maboro]

it's breaking change from the perspective of public API, the code looks good, but we shouldn't merge this PR to main as long as we're publishing 4.x from main

[kkafar]

Maybe you're right actually. TBH I'm no longer sure myself. We need to define in readme what is the public API - only things exported directly from react-native-screens.

[kkafar]

Looks good. I classified this as a breaking change for some reason in the ticket description. Before merging, could you take a look at how Expo & react-navigation uses it. I'm sure that Expo does, react-navigation might not use the feature flags, but not sure.

Please check whether this change will break them or not.

[t0maboro]

Looks good. I classified this as a breaking change for some reason in the ticket description. Before merging, could you take a look at how Expo & react-navigation uses it. I'm sure that Expo does, react-navigation might not use the feature flags, but not sure.

Please check whether this change will break them or not.

Please keep in mind that feature flags can be used inside end-users' apps, not only downstream libs

[kkafar]

Okay, I think @t0maboro is right here. Let's wait with this PR until branch cut, as decided in the ticket description.