feat: add search field color

[WoLewicki]

Description

Added option to set color of text in iOS search bar.

Changes

Added new prop to SearchBar.m and types.
Added checks for availability of iOS 13 in proper places.

Test code and steps to reproduce

Test758.tsx in TestsExample app.

Checklist

• Included code example that can be used to test this change
• Updated TS types
• Updated documentation:
  • https://github.com/software-mansion/react-native-screens/blob/master/guides/GUIDE_FOR_LIBRARY_AUTHORS.md
  • https://github.com/software-mansion/react-native-screens/blob/master/native-stack/README.md
  • https://github.com/software-mansion/react-native-screens/blob/master/createNativeStackNavigator/README.md
  • https://github.com/software-mansion/react-native-screens/blob/master/src/types.tsx
  • https://github.com/software-mansion/react-native-screens/blob/master/src/native-stack/types.tsx
• Ensured that CI passes

[nandorojo]

Hey @WoLewicki, I had some brief feedback about the search bar. It's working really well for me. Adds a total native feel to the app. I just had two points of feedback that I think could help it a lot.

1. Hide the title

I'd expect this code to hide the title above the search bar, bringing the search bar up to the top. However, it produces this result:

Maybe an alternate API could be:

hideNavigationBar: "always" | "while typing" | "never"

2. keyboardAppearance

My app is dark mode, so I'd love to be able to add keyboardAppearance="dark" to the keyboard.

Thank you so much for this awesome feature!

[WoLewicki]

We are always open for PRs with new functionalities 🎉 I am not sure why changing the title to empty string would collapse the title part of the header, and for the hideNavigationBar, cannot it be done in code in the events like onFocus and onBlur of the searchBar?

[nandorojo]

Yeah on second thought, an empty title shouldn't collapse the nav bar. I suppose I just wanted a way to have the nav bar always hidden. But I worked around it and added content to the header, so no worries.