This PR migrates the Plasma effect from SWT-OldSchoolEffect
to the SWT Graphics Example.

Changes:
- Implemented PlasmaTab.java extending AnimatedGraphicsTab
- Registered the new tab in GraphicsExample.java
- Added descriptive strings to examples_graphics.properties

Contributes to #3189

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>