Android Adaptive icons conflict with plugins

# Bug Report

## Problem

colors.xml gets overwritten by plugins, making it appear that the documentation is incorrect

### What is expected to happen?

colors.xml should write the content from your config.xml, but popular plugins overwrite this

### What does actually happen?

cordova-plugin-firebasex: Updated colors.xml with accent color

## Information

The this plugin `cordova-plugin-firebasex` overwrites the colors.xml file, which overwrites what is in the documentation. I'm not saying the functionality of the plugin is correct, but when you use it and try to implement based on the documentation it fails.

Either the documentation should mention this caveat that other plugins may overwrite the colors.xml, or to specify a different xml file name since any name can be used, for example I used brand.xml

### Command or Code

https://cordova.apache.org/docs/en/latest/config_ref/images.html#adaptive-icon-with-colors

### Environment, Platform, Device

Pixel 3 latest Android

### Version information

Building using cordova cli

## Checklist

- [x] I searched for existing GitHub issues
- [x] I updated all Cordova tooling to most recent version
- [x] I included all the necessary information above

Start with the adaptive-icon-with-colors section at the linked documentation URL and compare its guidance with the reported cordova-plugin-firebasex behavior. Update the documentation to clearly explain the colors.xml conflict or the alternative XML filename approach; done means the page no longer implies the configuration works unchanged with that plugin.

Written by the indexing model from the issue text.