Fix input margin inconsistency

What does this MR do?

The three consecutive checkbox inputs have different margin-bottom. Add class to make margin-bottom 0

Before the fix:

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• EE specific content should be in the top level /ee folder
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