feat: add metrics for test {instance} count (#969) #3971

Job	Run time
Build Worker / Build App	1m 16s
Run Lint / Run Lint	6s
Codecov Startup / Codecov Startup	13s
Test / Test	4m 52s
Build Self Hosted Worker / Build Self Hosted App	1m 47s
Push Staging Image / Push Release Image	0s
Push Staging Image / Push Rolling Image	0s
Push Staging Image / Push staging Image	1m 17s
Push Production Image / Push production Image	1m 22s
Push Production Image / Push Release Image	0s
Push Production Image / Push Rolling Image	0s
Build Self Hosted Worker / Push Self Hosted Release Image	0s
Build Self Hosted Worker / Push Self Hosted Image	0s
Push Self Hosted Image / Build Self Hosted App	58s
Push Self Hosted Image / Push Self Hosted Image	1m 37s
Push Self Hosted Image / Push Self Hosted Release Image	0s
	13m 28s

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