Fix bad image permissions

What does this MR do?

We were seeing issues from gitlab master runs due to a +x bit applied to the images.

This MR changes permissions to 644

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

/cc @rdickenson @niskhakova