None value fields are not being handled correctly in ContainerRegistryNode GQL

[jopemachine]

Summary  

• Values in the database should not be changed when no value is provided.

Steps to Reproduce  

1. Update the registry information in the WebUI and call the ModifyContainerRegistryNode API.
2. Check how the values of fields, when not provided, are changed in the database

Expected Behavior  

• Values in the database should not be changed when no value is provided.

Actual Behavior  

• Fields not provided, are changed to NULL in the database.

Logs/Errors  

None

[jopemachine]

If we treat null as a missing value, it causes an issue where we can't insert null into nullable columns like DB username and password.

This issue can be resolved by using the new V2 mutation introduced in #3418.
So I'll close this PR as not planned.