save comp to persist logo_icon

[bbearce]

@ mention of reviewers

@ihsaan-ullah @Didayolo

A brief description of the purpose of the changes contained in this PR.

Upon comp logo upload in competition editor, the logo_icon minio path isn't being updated (even though logo icon was being created). This change makes a specific call to save the competition post making a logo_icon.

Basically the competition.save method is saving everything about a competition when you save from the ui, except the new small icon it created. So even though we do an initial save with super().save(*args, **kwargs), we now resave after making the small logo to ensure the new path is reflected in the database.

Issues this PR resolves

• Small logo update when updating logo from editor #1390

A checklist for hand testing

• upload competition of find existing one
• upload new logo and save competition
• go to /admin and look into the competition record. The paths for both new logos should be similar with the exception of "_icon" in the icon path.
• 

Any relevant files for testing

• any comp

Checklist

• Code review by me
• Hand tested by me
• I'm proud of my work
• Code review by reviewer
• Hand tested by reviewer
• CircleCi tests are passing
• Ready to merge