Add SimpleSelect Component

[jenny-s51]

Description

The SimpleSelect component (see: https://github.com/opendatahub-io/kubeflow-ui-essentials/blob/main/components/SimpleSelect.tsx) is used across AI products, notably in toolbars, to provide a streamlined selection experience. Integrating this component into react-component-groups will promote its reuse across different AI applications.

Benefits

• Consistent user experience for select elements across applications.

• Simplifies development for AI applications by providing a pre-built, well-tested component.

Proposed Solution

Add support for this by creating a SimpleSelect component within the PatternFly React Component Groups.

Work Items

• Implement the SimpleSelect within react-component-groups with the default PF theme.

• Address MUI theming and demo integration, including context and a checkbox/switch, in a follow-up task.

[nicolethoen]

PatternFly has implemented a simple select - there's a case we could make for moving it into component groups, but I don't think it's necessary? Please let me know if you have an issue with where it lives, @jenny-s51

https://www.patternfly.org/components/menus/select/react-templates#simple

I can reopen this if we want to explore that case more.