Add file name in staged / unstaged views

### Is your feature request related to a problem? Please describe.
Proposal is to add the file name in Staged / Unstaged views.

### Describe the solution you'd like
Currently the Unstaged view title looks like
```
[0]-Unstaged changes-----
```
I'd like the change to look something like
```
[0]-Unstaged changes--/Workflows/Helpers/QueueManager.cs --
```
### Describe alternatives you've considered
Another alternative is to keep the row from `[2]-Files` highlighted when we switch to the changes view.

### Additional context
The reason for this request is while reviewing a large change set or context switching a lot, it's easy to lose track of which file the Unstaged changes window is pointing to. Although you can scroll to the top to see what files are getting diffed, it can be a bit tedious to go back and forth

Start by locating the code that renders the Staged and Unstaged views in lazygit, then run the application and reproduce the file-switching workflow described in the issue. The change is done when the Unstaged view identifies its selected file in the title, or the selected row remains highlighted when switching views, with the behavior verified manually.

Written by the indexing model from the issue text.