Add global label length limits #11

Job	Run time
More Go tests	8m 8s
Go tests on Windows	8m 44s
Compliance testing	7m 52s
Check generated parser	1m 13s
Mixins tests	3m 9s
UI tests	2m 15s
golangci-lint	3m 13s
Build Prometheus for common architectures (2)	11m 39s
Go tests	23m 10s
Build Prometheus for common architectures (0)	11m 30s
Build Prometheus for common architectures (1)	11m 27s
Go tests with previous Go version	12m 27s
codeql / Analyze (javascript)	1m 18s
fuzzing / Run Go Fuzz Tests (FuzzParseOpenMetric)	6m 36s
fuzzing / Run Go Fuzz Tests (FuzzParseMetricText)	6m 36s
fuzzing / Run Go Fuzz Tests (FuzzParseExpr)	6m 43s
fuzzing / Run Go Fuzz Tests (FuzzParseMetricSelector)	6m 43s
Build Prometheus for all architectures	0s
Report status of build Prometheus for all architectures	0s
fuzzing / Fuzzing	4s
Publish UI on npm Registry	1m 44s
Publish main branch artifacts	0s
Publish release artefacts	0s
	2h 14m 31s

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