[services] Tunnelbroker - Fix DatabaseManagerTest.cpp build error on non-closed brackets

Summary:
Fix DatabaseManagerTest.cpp build error on non-closed brackets which was discovered during the new builds:

DatabaseManagerTest.cpp:185:80: error: expected ')'
[build]       "mobile:EMQNoQ7b2ueEmQ4QsevRWlXxFCNt055y20T1PHdoYAQRt0S6TLzZWNM6XSvdWqxm";

Linear task: ENG-1067

Test Plan: Run yarn test-tunnelbroker-service to build and run the tests.

Reviewers: karol-bisztyga, palys-swm, varun, ashoat

Reviewed By: ashoat

Subscribers: ashoat, palys-swm, Adrian, atul, karol-bisztyga, yayabosh

Differential Revision: https://phabricator.ashoat.com/D3881