Incorrect `UploadApiErrorResponse` type

## Bug report for Cloudinary NPM SDK
Before proceeding, please update to latest version and test if the issue persists

## Describe the bug in a sentence or two.

The type for `UploadApiErrorResponse` is `{ message: string }` (plus other fields), but the actual API response is `{ error: { message: string } }` (note the `error` envelope).

## Issue Type (Can be multiple)

- [ ] Build - Can’t install or import the SDK
- [ ] Babel - Babel errors or cross browser issues
- [ ] Performance - Performance issues
- [ ] Behaviour - Functions aren’t working as expected (Such as generate URL)
- [ ] Documentation - Inconsistency between the docs and behaviour
- [x] Incorrect Types - For typescript users who are having problems with our d.ts files
- [ ] Other (Specify)

## Steps to reproduce

N/A

## Error screenshots

N/A

## Browsers (if issue relates to UI, else ignore)

N/A

## Versions and Libraries (fill in the version numbers)
Cloudinary_NPM SDK version - `2.6.1`
Node - 22.12.0
NPM - 10.9.0

## Config Files (Please paste the following files if possible)

N/A

## Repository

N/A