Dynamic sizing of the bottom sheet modal with less models

[catalinmiron]

In case when user choose to use only a subset of chat models, BottomSheet modal should resize automatically to fit the new list. This PR is going to take advantage of enableDynamicSizing prop that's now available to @gorhom/bottom-sheet 4.5.0+

Here's a quick demo of how things are going to act based on the ChatModels list selection

https://github.com/dabit3/react-native-ai/assets/2805320/71568924-490f-4dfa-92fd-c808051467f3

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Backdrop

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Backdrop behaviour video:

https://github.com/dabit3/react-native-ai/assets/2805320/047b51d2-6402-4b8f-bbff-b4c681d5f68e

[dabit3]

Yo, this is great, thank you so much @catalinmiron 🙏