[FEATURE] double location nginx problem

### What's needed and why?

So in services **you can use redirect** and in reverse proxy includes you **can add the custom conf file.**

My problem is: as soon as you provide custom conf and there already exist configured redirect it can oppose each other in a very unpleasant way , **so what need to be done?**

As soon as user upload custom conf file where statement **like location** used and there exist already redirect, **BunkerWeb UI should reject it, meaning not allow saving such setup at Reverse proxy config.**

### Implementations ideas (optional)

_No response_

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Start by locating the BunkerWeb UI reverse-proxy configuration save path and the handling for custom Nginx configuration, redirects, and location directives. Trace how these settings are validated before saving. Done means a reverse-proxy setup containing both a conflicting redirect and a custom location configuration is rejected rather than saved.

Written by the indexing model from the issue text.