Accessibility improvements in App Manager

### Please check before submitting an issue

- [x] I am using the latest version of App Manager
- [x] I have searched the issues and haven't found anything relevant
- [x] I have read the docs

### Describe a description of the new feature

The purpose of this issue is to list any potential accessibility issues and (if possible) fix them.
- [ ] In the Files page, the "Add" button does reliably support accessibility or keyboard navigation. This is because the underlying library (https://github.com/leinardi/FloatingActionButtonSpeedDial) does not reliably support accessibility features.
- [x] In the Running apps page, the header section does not state the memory and swap usage in a accessible-friendly way.
- [ ] In the Terminal page, the app should automatically navigate to the output widget once the user presses enter (in accessibility mode only) and/or automatically pronounce the new text (instead of whole text)

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

### Additional context

_No response_