chore(site): clarify Use permission in workspace sharing dropdown (#21861)

## Summary

Updates the description for the "Use" role in the workspace sharing
dropdown to explicitly mention that users with this permission can start
and stop the workspace, not just read and access it.

## Changes

- Updated the "Use" role description from "Can read and access this
workspace." to "Can read, access, start, and stop this workspace."

## Context

This clarification helps users understand the full scope of the "Use"
permission, which includes `ActionWorkspaceStart` and
`ActionWorkspaceStop` as defined in `coderd/database/db2sdk/db2sdk.go`.

---
*Created on behalf of @geokat*

Co-authored-by: blink-so[bot] <211532188+blink-so[bot]@users.noreply.github.com>

site/src/modules/workspaces/WorkspaceSharingForm/WorkspaceSharingForm.tsx

@@ -68,7 +68,7 @@ const RoleSelect: FC<RoleSelectProps> = ({
 				<SelectItem value="use" className="flex-col items-start py-2 w-64">
 					<div className="font-medium text-content-primary">Use</div>
 					<div className="text-xs text-content-secondary leading-snug mt-0.5">
-						Can read and access this workspace.
+						Can read, access, start, and stop this workspace.
 					</div>
 				</SelectItem>
 				<SelectItem value="admin" className="flex-col items-start py-2 w-64">