Fix loading icon position in "shareWith" field

[danxuliu]

When searching or selecting a sharee in the shareWith field a loading icon is shown. However, as the icon had a relative position and the shareWith field uses the full width of the share dropdown the icon was shown in a new line below the field. Moreover, due to its right CSS property the icon was also shown outside the dropdown itself. Now, during the search for or the selection of a sharee, the loading icon replaces the information icon shown in the shareWith field, just like done in the sharing section of the server.

Before (the icon is hardly visible, I should have used another background, I know :-) ):

After:

This should be backported to Nextcloud 13. It also happens in Nextcloud 12... worth a backport there?

@nextcloud/designers

[MorrisJobke]

Backported and tested - stable13 be8b141

[MorrisJobke]

Let's not do it for stable12 for now.