[5.x] Fix issue with AssetsFieldtype upload controls hidden on @sm size

[PatrickJunod]

This PR fixes an issue where the AssetsFieldtype does not show the upload controls when the field does not have enough space to be shown.

It does so by flex-wrapping the content of the .assets-fieldtype .assets-fieldtype-picker selector:

11436_480.mov

Remove extra top margin in alt text

It also removes the extra top margin in the asset upload control

Before:

After:

Fixes

Fixes #11436

[daun]

I wonder if this might be improved further with an ultra-short version of the upload prompt for the small size? Could also fall back to the full-length version if not translated yet.

E.g.: "Upload or drop file" / "Hochladen oder reinziehen"

[edalzell]

I wonder if this might be improved further with an ultra-short version of the upload prompt for the small size? Could also fall back to the full-length version if not translated yet.

E.g.: "Upload or drop file" / "Hochladen oder reinziehen"

yas plz fren

[jasonvarga]

Good enough for now. This might end up changing in v6 anyway. Thanks!