Move link handlers back to proposed

Part of #91606

src/vs/workbench/api/common/extHost.api.impl.ts

@@ -570,6 +570,7 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 				return extHostTerminalService.createTerminal(nameOrOptions, shellPath, shellArgs);
 			},
 			registerTerminalLinkHandler(handler: vscode.TerminalLinkHandler): vscode.Disposable {
+				checkProposedApiEnabled(extension);
 				return extHostTerminalService.registerLinkHandler(handler);
 			},
 			registerTreeDataProvider(viewId: string, treeDataProvider: vscode.TreeDataProvider<any>): vscode.Disposable {