[Ubuntu] Use mozilla official apt repo for installing firefox

[TerrorJack]

The mozillateam ppa contains outdated firefox version. Mozilla has an official apt repo that provides up-to-date firefox package in sync with other OTA release channels, so use that instead.

Description

New tool, Bug fixing, or Improvement? Please include a summary of the change and which issue is fixed. Also include relevant motivation and context. For new tools, please provide total size and installation time.

Related issue:

Check list

• [ ] Related issue / work item is attached
• [ ] Tests are written (if applicable)
• [ ] Documentation is updated (if applicable)
• [ ] Changes are tested and related VM images are successfully generated