desktop: proxy config not supported through daemon.json/config.json (#20905)

## Description

Docker Desktop does not respect proxy configuration through config.json
(cli) or daemon.json (dameon). Proxy config for DD is only supported
through the settings menu or via settings management.

## Related issues or tickets

docker/pinata#30436

Signed-off-by: David Karlsson <[email protected]>

Author: dvdksn

content/manuals/desktop/settings.md

@@ -260,8 +260,12 @@ The HTTPS proxy settings used for scanning images are set using the `HTTPS_PROXY
 > If you are using a PAC file hosted on a web server, make sure to add the MIME type `application/x-ns-proxy-autoconfig` for the `.pac` file extension on the server or website. Without this configuration, the PAC file may not be parsed correctly.
 
 > [!IMPORTANT]
+> You cannot configure the proxy settings using the Docker daemon configuration
+> file (`daemon.json`), and we recommend you do not configure the proxy
+> settings via the Docker CLI configuration file (`config.json`).
 >
-> You do not need to separately configure proxy settings for the Docker CLI or Docker daemon.
+> To manage proxy configurations for Docker Desktop, configure the settings in
+> the Docker Desktop app or use [Settings Management](/manuals/security/for-admins/hardened-desktop/settings-management/_index.md).
 
 #### Proxy authentication
 

content/manuals/engine/daemon/proxy.md

@@ -23,6 +23,11 @@ This page describes how to configure a proxy for the Docker daemon. For
 instructions on configuring proxy settings for the Docker CLI, see [Configure
 Docker CLI to use a proxy server](/manuals/engine/cli/proxy.md).
 
+> [!IMPORTANT]
+> Proxy configurations specified in the `daemon.json` are ignored by Docker
+> Desktop. If you use Docker Desktop, you can configure proxies using the
+> [Docker Desktop settings](/manuals/desktop/settings.md#proxies).
+
 There are two ways you can configure these settings:
 
 - [Configuring the daemon](#daemon-configuration) through a configuration file or CLI flags