Fix button inconsistencies on blob header

• Fix button styles in repo header
• Fix button inconsistencies on blob header

What does this MR do?

This MR fixes #281571 (closed) which was introduced by !45005 (merged).

Screenshots (strongly suggested)

Before	After

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

References

• Related to #281571 (closed)