Fix auto theme for status pages on custom domains

[crystalcommunication]

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Description

Fixes #3294

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• User interface (UI)

Checklist

• My code follows the style guidelines of this project
• I ran ESLint and other linters for modified files
• I have performed a self-review of my own code and tested it
• I have commented my code, particularly in hard-to-understand areas
  (including JSDoc for methods)
• My changes generate no new warnings
• My code needed automated testing. I have added them (this is optional task)

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