Adds metrics for client-side event emission and subscription (#14785) #15835

Job	Run time
docker, python:3.9	5m 15s
docker, python:3.10	5m 12s
docker, python:3.11	4m 40s
docker, python:3.12	5m 3s
Server Tests - python:3.9, postgres:14	3m 29s
Server Tests - python:3.10, postgres:14	3m 27s
Server Tests - python:3.11, postgres:14	3m 9s
Server Tests - python:3.12, postgres:14	3m 33s
Server Tests - python:3.9, sqlite	4m 57s
Server Tests - python:3.10, sqlite	4m 50s
Server Tests - python:3.11, sqlite	4m 33s
Server Tests - python:3.12, sqlite	5m 13s
Client Tests - python:3.9, postgres:14	6m 57s
Client Tests - python:3.10, postgres:14	6m 59s
Client Tests - python:3.11, postgres:14	6m 27s
Client Tests - python:3.12, postgres:14	6m 48s
	1h 20m 32s

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