Description

1. Prevent the right-click from selecting multiple items when the "single-click" option is active and Ctrl, Command Key or Multiple selecting is disabled.
2. When you left-click on a selected item, if the Ctrl or Command keys are pressed or the "Multiple selecting" option is active, the item is deselected; otherwise, all previously selected items are deselected and only the item that triggered the event is selected.

Additional Information

Closes #5585

Checklist

Before submitting your PR, please indicate which issues are either fixed or closed by this PR. See GitHub Help: Closing issues using keywords.

• I am aware the project is currently in maintenance-only mode. See README
• I am aware that translations MUST be made through Transifex and that this PR is NOT a translation update
• I am making a PR against the master branch.
• I am sure File Browser can be successfully built. See builds and development.