The Cisco Umbrella roaming client and DNSMasq compete for the same resources—namely port 53 for DNS—and are considered incompatible with each other.
What to do
The Umbrella roaming client works by acting as a DNS proxy server and listening on 127.0.0.1 (localhost) port 53. It is fundamentally incompatible with any other service that tries to do the same, which is what DNSMasq does.
The only workaround is to use one or the other service, but not both. The expected behavior with both DNSMasq and the Umbrella roaming client installed is that only one of the two will work, usually the first of the two services to start.