Challenge listing's loading with a flickering image even after reaching the end of the list.

[sandhiyakavi]

Description:
Challenge listing's loading with a flickering image even after reaching the end of the list.

Steps to Reproduce:

1. Click My Challenges link in the right side menu bar.

Screenshot:

Challenge_listing_loading_issue.zip

[SathyaJayabal]

Even after he last challenges are retrieved, the FE keeps calling the api.
api calls.mov.zip

[sushilshinde]

@LieutenantRoger PR?

[LieutenantRoger]

@sushilshinde I have submitted the code to the branch feature-refactor-challengelist-fixes directly per the instruction in the slack.