fix(FilePreview): limit preview size to 384px at upload

[Antreesy]

☑️ Resolves

• Fix regression from fix(FilePreview): use original size for uploaded image files #13147
• max-height: 100% takes the height of parent, which is .image-container, which is not limited
• images larger than 384px shown at full-size (especiall if photos app is disabled)

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

🏚️ Before	🏡 After

🏁 Checklist

• 🌏 Tested with different browsers / clients:
  • Chromium (Chrome / Edge / Opera / Brave)
  • Firefox
  • Safari
  • Talk Desktop
  • Not risky to browser differences / client
• 🖌️ Design was reviewed, approved or inspired by the design team
• ⛑️ Tests are included or not possible
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required

[DorraJaouad]

Height works well