Can not save custom DNS when IPv4 set to Automatic

[freezurbern]

Checklist

• I have updated to the latest available Home Assistant version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in safe mode to rule out problems with unsupported custom resources.

Describe the issue you are experiencing

Hello,
I found I am allowed to edit the DNS servers ("ADD DNS SERVER" button is present and not disabled) but the entry does not save when IPv4 is set to Automatic. The DNS servers are reset to those provided by my router.

Describe the behavior you expected

I would expect the "ADD DNS SERVER" button to not appear until IPv4 is set to Static.
I would also expect the DNS Server fields to be disabled if their changes are not persistent after pressing "Save".

I would prefer to have a middle-of-the-road approach, similar to Windows and Ubuntu:

• Allow DHCP for getting an IP address.
• Allow setting custom DNS server entries to override those provided by DHCP.

Steps to reproduce the issue

1. Navigate to /config/network
2. Set IPv4 to Automatic
3. Change or add a DNS Server entry
4. Click SAVE and see the DNS Server entries are reset to the router's suggestions.

What version of Home Assistant Core has the issue?

2024.12.3

What was the last working version of Home Assistant Core?

No response

In which browser are you experiencing the issue with?

Google Chrome 131.0.6778.140

Which operating system are you using to run this browser?

Windows 10

State of relevant entities

No response

Problem-relevant frontend configuration

No response

Javascript errors shown in your browser console/inspector

No response

Additional information

No response