fix: conditional for disabled postgres

[codyshoffner]

Description

• Added conditionals to suppress "Error from server (NotFound): packages.uds.dev "postgres" not found" error message when setting postgresql.enabled: false
• Tested locally with postgresql.enabled: false and confirmed no error mesages.
• Tested locally with postgres.enabled: true to verify existing functionality.

Related Issue

Fixes #126

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed

Screenshot

Screenshot showing the shim still working on upgrade when postgres is enabled