Unified Monitoring Agent enhancements in multiple regions

The following Unified Monitoring Agent changes have been implemented for South Korea North (Chuncheon), India South (Hyderabad), Australia Southeast (Melbourne), Japan Central (Osaka), Australia East (Sydney), Canada Southeast (Montreal), Netherlands Northwest (Amsterdam), Switzerland North (Zurich), Germany Central (Frankfurt), UAE East (Dubai), Saudi Arabia West (Jeddah), Chile Central (Santiago), Brazil East (Sao Paulo), UK South (London), US East (Ashburn), US West (Phoenix), and US West (San Jose):

• The realm domain is now obtained from the instance metadata service, rather than the SDK.
• Added support for resource principal to sign HTTP requests.
• The new nested JSON parser type has been added.
• Metrics related to the validity of the configuration downloaded by the agent are now emitted.
• Warning message issues have been fixed.