PICARD-3234: Fix columns being restored with 0 width

[phw]

Summary

• This is a…
  • Bug fix
  • Feature addition
  • Refactoring
  • Minor / simple change (like a typo)
  • Other
• Describe this change in 1-2 sentences:

Problem

• JIRA ticket (optional): PICARD-3234

When loading the stored columns setting invisible columns would be set to a width of 0. This would call issues with columns not being shown after enabling them.

Solution

Set the width to the default column width if it would be 0.

AI Usage

In accordance with the AI use policy portion of the MetaBrainz Contribution Guidelines, the level of AI/LLM use in the development of this Pull Request is:

• No AI/LLM use
• Minimal use (e.g. autocompletion)
• Moderate use (e.g. suggestions regarding code fragments)
• Significant use (e.g. code structure, tests development, etc.)
• Primarily AI developed
• Other (please specify below)

Action

Additional actions required:

• Update Picard documentation (please include a reference to this PR)
• Other (please specify below)

[zas]

LGTM