Fix #7601: Force locale & calendar for news date decoding formatter

[kylehickinson]

It seems somehow on certain devices in the UK, date decoding is failing. I couldn't reproduce locally unfortunately so this solution is untested though hopefully the correct one

Summary of Changes

This pull request fixes #7601

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()
• New or updated UI has been tested across:
  • Light & dark mode
  • Different size classes (iPhone, landscape, iPad)
  • Different dynamic type sizes

Reviewer Checklist:

• Issues include necessary QA labels:
  • QA/(Yes|No)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate unit test coverage exists to prevent regressions.
• Adequate test plan exists for QA to validate (if applicable).
• Issue and pull request is assigned to a milestone (should happen at merge time).