enhance: change from to std::ranges::find_if in Chat::getPrivateChannel

[dudantas]

Description

This pull request refactors the iteration and conditional logic used to find a specific PrivateChatChannel in privateChannels to use std::ranges::find_if. The updated version of the code improves readability by reducing boilerplate, leveraging structured bindings and modern C++ features.

Behaviour

Actual

Iterating over privateChannels using a for loop and checking if the owner's GUID matches the player's GUID manually.

Expected

Using std::ranges::find_if to streamline the search for the private channel, simplifying the code by using a lambda and structured bindings.

Type of change

• [x] Code refactor (non-breaking change that improves the code quality)

Checklist

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I checked the PR checks reports
• [x] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation (not applicable)
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works (not applicable)