Make Sensor source popup wider

[lepa22]

Description

The popup that allows you to select a source for Sensors is not wide enough, so the text gets truncated, making the selection of a source difficult. The pop up should be made wider, and adaptable to the contents up to a maximum width. In cases where a source is longer than the set maximum width (not sure if a source can be that long), it would be nice if a tooltip were shown with the full name of the source.

The same happens to the (newly created) Used Memory selection type, but I'm not opening a new issue for this, since the fix should be the same and to avoid cluttering the issues section.

Steps to Reproduce

1. Install and enable the extension.
2. Go to Sensors tab.
3. Click the Sensor 1/2 Source value.
4. The dropdown shows the available sources, but they are truncated, so not easy to select.

Screenshots

Environment

• Astra Monitor Version: v3 (not yet released)
• GNOME Version: 45.3
• Operating System and Version: Fedora 39

[ljuzig]

Fixed: