ddtrace/tracer: support reading statsd port from tracer

[hannahkm]

What does this PR do?

• Adds an internal ignore to the agent to be used during testing user set statsd ports
• Adapts expected format of statsd port

Motivation

The issue was reported by #1802 . This PR follows up on the work on #1803 .

Reviewer's Checklist

• Changed code has unit tests for its functionality at or near 100% coverage.
• System-Tests covering this feature have been added and enabled with the va.b.c-dev version tag.
• There is a benchmark for any new code, or changes to existing code.
• If this interacts with the agent in a new way, a system test has been added.
• Add an appropriate team label so this PR gets put in the right place for the release notes.
• Non-trivial go.mod changes, e.g. adding new modules, are reviewed by @DataDog/dd-trace-go-guild.

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[pr-commenter]

Benchmarks

Benchmark execution time: 2024-11-05 19:15:00

Comparing candidate commit 0eea826 in PR branch hannah/fix-statsd-port with baseline commit 2d679b9 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 58 metrics, 1 unstable metrics.