Use ruby-magic-static for the time being (bump to 0.3.4)

What does this MR do?

When using the regular ruby-magic Gem we're running into issues with not being able to download the libmagic library. In merge request ruby-magic!5 (merged) we added a quick workaround to at least let us continue to deploy. This commit switches over our Rails application to use that fork for the time being.

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have not included a changelog entry because this is a backstage and temporary change
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content