Add a new playground component to rntester (#46632)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/46632

Changelog: [General][Added] Add Playground to RNTester for testing out features & submitting reproducers.

**Context**

- Adding the Playground from Catalyst to RNTester
- This should help folks test React Native features for a particular version

**Change**

- Add a new playground component to RNTester
- Add a new reducer action for opening an example from navbar press
- Fixed typing issues
- Add icon from this fb asset pack: https://www.internalfb.com/assets/set/facebook_icons/nucleus-beaker/variant_outline-size_24?q=beaker
- Matched background color using this imagemagick script

**dark**
```
convert input.png -fill 'rgb(178,180,186)' -colorize 100% output.png
```
**light**
```
convert input.png -fill 'rgb(81,82,84)' -colorize 100% output.png
```

Reviewed By: NickGerleman

Differential Revision: D61972594

fbshipit-source-id: 4a5523a84a6ef09d3266d5f56825907bd3fbe4b5