Output: sync WebSocket settings with UI

[iibaranov-IG]

SetOutputSettings updated the live ndi_output instance, while the DistroAV output dialog continued to load its name and groups from the plugin configuration. As a result, a WebSocket change succeeded but the dialog displayed the previous values.

This change identifies updates for DistroAV's managed main and preview outputs, mirrors their ndi_name and ndi_groups into the corresponding plugin configuration, and persists changes only when values differ. Dedicated NDI outputs are unaffected.

Closes #1438.

Validation:

• git diff --check
• upstream CI build and formatting matrix requested by this PR
• local upstream macOS build could not run because the available command-line environment does not include the full Xcode generator

[BitRate27]

Thanks for taking the initiative to fix this issue!

I tested your changes with the
obs_output_settings_modify_getoutputstatus.html
web page.

I found the following issues:

1. Changing the name or group does not change the NDI name/group currently being output
2. Have to exit the Output settings dialog and re-enter to see the name/group change
3. You can only change the name/group using web sockets if currently outputting

These scenarios are already fixed and tested in #1472, it is just pending a merge.
1472 also supports enabling the outputs through web sockets. It would be very useful for someone else to test 1472. It would also be helpful if you could do a code review of 1472.