Fix: #1350 Icon box links not working properly

[frimpongopoku]

Summary / Highlights

I checked and found that we are actually checking for all the weird cases for user input. Looks like the fault was from __is_custom_site -- it cant be trusted. So I just implemented a better check for the app to accurately determine when we are on a MassEnergize domain... then show the appropriate link. (i.e. prefix with subdomain)

Details (Give details about what this PR accomplishes, include any screenshots etc.)

Testing Steps (Provide details on how your changes can be tested)

Requirements

• [x] I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• [x] I've tested my changes manually.
• [ ] I've added unit tests to my PR.

Transparency (Project board)

• [x] I've given my PR a meaningful title.
• [x] I linked this PR to the relevant issue.
• [ ] I moved the linked issue from the "Sprint backlog" to "In progress" when I started this.
• [ ] I moved the linked issue to "QA Verification" now that it is ready to merge.

What kind of change does this PR introduce? (check at least one)

• [x] Bugfix
• [ ] Feature
• [ ] Performance improvement
• [ ] Feature removal
• [ ] Code style update
• [ ] Refactor
• [ ] Docs
• [ ] Build-related changes
• [ ] Other, please describe:

Does this PR introduce a breaking change? (check one)

• [ ] Yes
• [x] No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• [x] It's submitted to the dev branch or to a feature branch, not the main branch
• [x] When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• [ ] All tests are passing:
• [ ] New/updated tests are included

Other information: Any otherthing we need to know