Add 'show-patched-versions' option to configuration and update summary handling

- Introduced 'show-patched-versions' input in action.yml to control visibility of patched versions in vulnerability summaries.
- Updated default configuration and related functions to handle the new option.
- Enhanced tests to verify behavior with and without the patched version column.

src/utils.ts

@@ -33,7 +33,7 @@ export function renderUrl(url: string | null, text: string): string {
   }
 }
 
-function isEnterprise(): boolean {
+export function isEnterprise(): boolean {
   const serverUrl = new URL(
     process.env['GITHUB_SERVER_URL'] ?? 'https://github.com'
   )