feat: Drop in Attachments

[lesquive]

Description: This PR enables file drag-and-drop functionality within the Chat window. When a user drags a file over the designated drop zone, the component's background color dynamically changes to offer visual feedback. This functionality leverages the capabilities of the react-dropzone library.

accepted files:

    accept: {
      "image/*": [".png", ".jpeg", ".jpg", ".gif"],
    },

Contributing to Twilio

All third-party contributors acknowledge that any contributions they provide will be made under the same open-source license that the open-source project is provided under.

• [ x] I acknowledge that all my contributions will be made under the project's license.

[berkus]

@lesquive hi, please resolve the conflicts!

[lesquive]

@berkus merge conflicts resolved