v1 bundle unpacking: use column label as title

@ mention of reviewers`

@Didayolo`

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

While unpacking V1 bundle, label of column was not used as title in Leaderboard.

Now, with the changes made, the following will happen:

1. V1 bundle has label for column: label is used as title. Example below:

2. V1 bundle has no label for column: key is used as title. Example below:

Issues this PR resolves

#375 (closed) point 1

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