chore: Prefer MAX_IMAGE_SIZE_MB over MAX_IMAGE_SIZE_BYTE

What does this MR do?

Prefer MAX_IMAGE_SIZE_MB over MAX_IMAGE_SIZE_BYTE as it's more readable, maintainable (less bumps), and the specificity doesn't really matter.

Does this MR meet the acceptance criteria?

• Job definition updated, if necessary
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer