chore: remove unused chat files (#36861)

## Description
I forgot to delete it in the previous issue. 

## Automation

/ok-to-test tags="@tag.Sanity"

### 🔍 Cypress test results
<!-- This is an auto-generated comment: Cypress test results  -->
> [!TIP]
> 🟢 🟢 🟢 All cypress tests have passed! 🎉 🎉 🎉
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/11325795465>
> Commit: 6ec1c0f
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/rundetails-65890b3c81d7400d08fa9ee5?branch=master&workflowId=11325795465&attempt=1"
target="_blank">Cypress dashboard</a>.
> Tags: `@tag.Sanity`
> Spec:
> <hr>Mon, 14 Oct 2024 11:06:16 UTC
<!-- end of auto-generated comment: Cypress test results  -->


## Communication
Should the DevRel and Marketing teams inform users about this change?
- [ ] Yes
- [x] No


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
- Removed the `ChatInput` component, which previously provided a
customizable text input area with features for error handling and
dynamic resizing.

- **Chores**
- Deleted the associated TypeScript type definitions for
`ChatInputProps`, simplifying the component structure.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->