feat: add count/before/start info to `onChange` event

[hannojg]

Details

As part of an effort to fix a long standing bug in expensify / react-native's text input I need to update the web implementation to work as the react-native's native change:

Goal: align with:

• https://github.com/facebook/react-native/pull/45248

In this PR the onChange event is send with the range in which the new changes occurred. The range is encoded as three values:

• start: The position in the new text where the changes started occuring
• count: The length of the newly changed text
• before: The length of the text before the changes.

Here are a few examples to better understand this:

• Initial: "Hello"
• Update to: "Hello!"
• start: 5 (end of Hello)
• count: 1 (the ! was added)
• before: 0 (no text was replaced)

Second example:

• Initial: "Hello"
• Update to: "He0o"
• start: 2 (after the e)
• count: 1 (the 0 was added)
• before: 2 (the text replaced ll had a length of 2)

This PR adds the same range info when we fire a onChange event.

Related Issues

https://github.com/Expensify/App/issues/37896

Manual Tests

Still need to add (will do tmrw) - can I maybe get a code review first?

Linked PRs

• https://github.com/Expensify/App/pull/44285

[github-actions[bot]]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[hannojg]

I have read the CLA Document and I hereby sign the CLA

[hannojg]

recheck

[BartoszGrajdek]

I haven't found any regressions 👍🏻