[a11y] Accessibility reports in 4.5.1

[JuancaG05]

Running an accessibility analysis for the current version 4.5.1, using the official Google tool Accessibility Scanner, we found there are some reports newly added in some of the screens that the original report covers:

• File list: the "Close" button represented by a cross in the bottom sheet of the 3-dot menu doesn't have a content description
• Share: when there is more than 1 row in the list of private shares and public links, all the equal buttons among rows have the same content description
• Manage accounts: when there is more than 1 row in the list of accounts, all the equal buttons among rows have the same content description

The other screens checked (Drawer menu, Spaces list and Image preview) are OK in terms of accessibility.