Add filtering to RNTester examples

[rickhanlonii]

This PR adds filtering to the examples in RNTester. This will allow us to filter the examples directly instead of scrolling (which is unreliable). Note, this replaces #22777

Additionally, it also:

• Adds and consolidates flow types for examples
• Updates all examples to export title description and examples consistently
• Refactors existing e2e tests to use the new filtering

Todo in a followup:

• Refactor remaining modules that include multiple examples but do not export them individually (and thus cannot be filtered)

Test Plan:

Here is an example of one of the tests that now use filtering:

[rickhanlonii]

In many of these files I moved the stylesheet declaration (or other code) above the example exports so that every example has the exports at the bottom for consistency

[rickhanlonii]

Many of the example files used static properties to declare the title and description. This didn't work great with flow types and is inconsistent with the other examples so I moved them all to the exports

[rickhanlonii]

This needed refactored to export multiple examples

[rickhanlonii]

I moved these types to shared/RNTesterTypes

[rickhanlonii]

Also needed to refactor this to export multiple examples

[rickhanlonii]

Here are the main changes in this pull

If there is only one example exported, we just show the single example. This should maintain the existing behavior for modules until they're refactored to export multiple examples.

If there's more than one example exported, we add a filter which will filter by the example title

[rickhanlonii]

cc @CodingItWrong

[rickhanlonii]

Spoke to @TheSavior and @CodingItWrong offline, closing this in favor of #22777 and breaking these changes out into multiple PRs