Fix missing reference and admin access bug

[jairoanaya]

Description

1. Fix reference issues on submissions.
2. Fix admin access issue on challenge phases.
3. Improve the general code for better readability and performance.

Related Issues

Missing reference on submissions module.
Fixing bug for admin accessing submissions.

Changes Made

Challenges.ex - improvement of existing submission validation functions.
Security.ex - improvement of functions to control non-gov log
Submission.ex - adding missing reference security

Screenshots (if applicable)

NA

Checklist

• PR is assigned to a project: Challenge_gov Board
• PR is assigned to a milestone: current sprint
• GH issues are assigned to the PR (under Development section on the right hand side)
• PR is assigned a reviewer, and requires code review and approval by a teammate
  - [] New functionality is tested and all tests are green
  - [ ] I have added unit tests for new functionality or updated existing tests for changes.
  - [ ] I have updated the documentation/README accordingly, if necessary.
  - [ ] If you have DB migration, it is a "safe" migration and you've confirmed it can be rolled back.
• If applicable, Controllers modified contain appropriate authorization plugs
• This PR has been reviewed by at least one other team member.