[dogstatsd] better use of the counter and gauges in the string interner

[remeh]

What does this PR do?

Improves how #20308 is using the internal telemetry to improve performances. We remarked a performance hit in that area with our nightly benchmarks.

Additional Notes

Added a basic micro-benchmark to validate performance improvements.

Before:

BenchmarkLoadOrStoreReset-10             1335985               900.7 ns/op

After:

BenchmarkLoadOrStoreReset-10            12263616               93.39 ns/op

Reviewer's Checklist

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