Refactor display builder island plugins and remove unused controls
- Removed icon definitions from various island plugins (e.g., BlockLibraryPanel, BuilderPanel, ComponentLibraryPanel, etc.) to streamline the codebase.
- Deleted the ControlsButtons plugin as it was deemed unnecessary.
- Introduced new button plugins: ExpandButton, HelpButton, and ThemeButton to enhance functionality.
- Updated ProfileViewBuilder to accommodate changes in dynamic tab handling and button configurations.
- Adjusted test configurations to reflect the removal of controls and the introduction of new buttons.
Closes #3616033