Patch config does not patch non read-only keys while a read-only key is included #2348

Versions

Core version is v6.0.5 (Latest: v6.0.5)
Web version is v6.0.2 (Latest: v6.0.2)
FTL version is v6.0.4 (Latest: v6.0.4)

Platform

• OS and version: Debian 12
• Platform: Docker

Expected behavior

A PATCH /config with a json payload of multiple fields where one of the keys are read-only results in a no-op.

This might be intended, however it's a bit confusing since making a POST /teleporter will just ignore all read-only keys, but in this case it simply ignores the request if a single key is read-only.

Is there another way to patch many config keys while ignoring read-only keys, without using teleporter?

Actual behavior / bug

It returns a 400 and has no effect on the other config keys requested to be patched.

Steps to reproduce

1. Set a read-only key
   FTLCONF_dns_ignoreLocalhost=true

2. Send a patch request
   PATCH /config

{
   "config":{
      "dns":{
         "ignoreLocalhost":false,
         "showDNSSEC":true
      }
   }
}

3. Returns 400 and does not update showDNSSEC

Debug Token

• URL:
  https://tricorder.pi-hole.net/vwM11we4/