Add chat completion concurrency logging (#733) #806

Job	Run time
build-and-smoke-freebuff-windows	4m 13s
build-freebuff	1m 36s
e2e-help-command	1m 7s
e2e-ads-behavior	1m 3s
e2e-agent-startup	2m 13s
e2e-startup	1m 2s
e2e-slash-commands	59s
e2e-version	1m 1s
e2e-code-edit	53s
e2e-terminal-command	1m 3s
	15m 10s

Provide feedback