Improve the selection color in the terminal

[kittaakos]

Describe the problem

The selection in the terminal is barely visible. It works with the default Theia themes.

terminal_selection.mp4

To reproduce

• Open a terminal in IDE2 (Ctrl+`),
• Select the content.

Expected behavior

Selected text in the terminal is visible with the Arduino themes.

Arduino IDE version

9ae3402

Operating system

macOS

Operating system version

12.5.1

Additional context

No response

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details