Admin Panel in mobile is not responsive

[paoliniluis]

Describe the bug
When getting into Settings from a mobile browser, the section is not responsive at all and it even displays the top bar wrong (you need to click on the edge on a blank part to exit the settings section)

Logs
NA

To Reproduce
Set up a Metabase instance and get into it with a mobile browser or desktop browser with iphone 6/7/8 dimensions

Expected behavior
The whole settings section to be responsive so I can tweak settings with the browser. Also, the top bar should have an accordion so I can exit the section without guessing where the gear is)

Screenshots

Information about your Metabase Installation:

• Your browser and the version: Brave latest
• Your operating system: Ubuntu LTS latest
• Your databases: None
• Metabase version: 40.5
• Metabase hosting environment: Docker
• Metabase internal database: H2

Severity
Cosmetic, but could be higher

Additional context
NA

[flamber]

Related to #15232 and #16176 and #16350/#16351 and probably other smaller issues. It is unlikely that Admin Panel will become fully responsive for tiny screens, but the navigation bar should at least be visible.