fix: resolve TypeScript errors for os field on connection logs

- Add optional chaining for userAgent.os.name in ConnectionLogRow.tsx
- Make os field optional in DiagnosticSessionConnection type to match Go SDK

site/src/pages/ConnectionLogPage/ConnectionLogRow/ConnectionLogRow.tsx

@@ -110,7 +110,7 @@ export const ConnectionLogRow: FC<ConnectionLogRowProps> = ({
 											{(connectionLog.os || userAgent?.os.name) && (
 												<div>
 													<h4 css={styles.connectionLogInfoheader}>OS:</h4>
-													<div>{connectionLog.os || userAgent.os.name}</div>
+													<div>{connectionLog.os || userAgent?.os?.name}</div>
 												</div>
 											)}
 											{userAgent?.browser.name && (

site/src/pages/OperatorDiagnosticPage/types.ts

@@ -115,7 +115,7 @@ export interface DiagnosticSessionConnection {
 	disconnected_at: string | null;
 	status: WorkspaceConnectionStatus;
 	exit_code: number | null;
-	os: string;
+	os?: string;
 	explanation: string;
 }