Add Refresh Button to Environment Selector in Session Launcher

### Description

The Environment (image) selector in the session launcher currently fetches the list of images when the page is first loaded. However, images may be added asynchronously, such as through user image commit functions. To accommodate this, we should add a refresh button to the Environment selector. This will allow users to manually refresh the list of available images to ensure they have access to the most up-to-date options.

#### Steps to Implement

1. Add a refresh button next to the Environment selector in the session launcher.
1. Implement functionality to re-fetch the list of available images when the refresh button is clicked.
1. Ensure that the UI updates to reflect any new images that have been added asynchronously.
#### Additional Context

- This feature is necessary to handle cases where images are added after the initial page load.
- Consider any potential performance impacts of re-fetching the image list.

JIRA Issue: FR-35