Custom database docker image reset to default for any unrelated change

[evgiz]

To Reproduce

1. Create a new postgres app
2. In advanced settings, set a custom docker image
3. Do an unrelated update (i.e update description)
4. Docker image name will be reset to postgres:18

Current vs. Expected behavior

Docker image should remain the same unless explicitly changed.

Provide environment information

Dokploy v0.28.6

Which area(s) are affected? (Select all that apply)

Databases

Are you deploying the applications where Dokploy is installed or on a remote server?

Same server where Dokploy is installed

Additional context

I believe this regression was introduced in this commit.

Looks like the update schema inherits the docker image default from the create schema, and therefore overwrites it on any change. This is likely also an issue for other databases/schemas.

Will you send a PR to fix it?

Maybe if I have time

[evgiz]

Looks like this might be related to #3883