chore: update mux.js to v7.0.3

[wseymour15]

Description

update mux.js to v7.0.3

This includes a fix for some unexpected 608 caption behavior.

Requirements Checklist

• [x] Feature implemented / Bug fixed
• [ ] If necessary, more likely in a feature request than a bug fix
  • [ ] Unit Tests updated or fixed
  • [ ] Docs/guides updated
  • [ ] Example created (starter template on JSBin)
• [ ] Reviewed by Two Core Contributors

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.27%. Comparing base (0e9d9d8) to head (3e36978).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1498 +/- ## ======================================= Coverage 86.27% 86.27% ======================================= Files 43 43 Lines 10884 10884 Branches 2504 2504 ======================================= Hits 9390 9390 Misses 1494 1494 ```

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