chore(config): migrate tracer.profilerHotspots

[mtoffl01]

What does this PR do?

Tracer migrates to using Config.profilerHotspots instead of its own config.profilerHotspots.

Motivation

datadoghq.atlassian.net/browse/APMAPI-1748

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.
• New code is free of linting errors. You can check this by running ./scripts/lint.sh locally.
• 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.

Unsure? Have a question? Request a review!

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-12-09 16:56:42

Comparing candidate commit 7ec2f1e in PR branch mtoff/profilerHotspots with baseline commit 78b2dc1 in branch main.

Found 0 performance improvements and 3 performance regressions! Performance is the same for 6 metrics, 0 unstable metrics.

scenario:BenchmarkSingleSpanRetention/no-rules-25

• 🟥 execution_time [+6.314µs; +7.404µs] or [+3.405%; +3.993%]

scenario:BenchmarkSingleSpanRetention/with-rules/match-all-25

• 🟥 execution_time [+6.147µs; +7.878µs] or [+3.210%; +4.114%]

scenario:BenchmarkSingleSpanRetention/with-rules/match-half-25

• 🟥 execution_time [+6.072µs; +7.452µs] or [+3.177%; +3.899%]

[codecov]

Codecov Report

❌ Patch coverage is 43.75000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 54.21%. Comparing base (3f840af) to head (7ec2f1e).
⚠️ Report is 80 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/config/config.go	10.00%	9 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
ddtrace/tracer/log.go	86.51% <100.00%> (ø)
ddtrace/tracer/option.go	85.18% <100.00%> (+0.56%)	⬆️
ddtrace/tracer/telemetry.go	87.50% <100.00%> (ø)
ddtrace/tracer/tracer.go	86.40% <100.00%> (+0.19%)	⬆️
internal/config/config.go	72.05% <10.00%> (-27.95%)	⬇️

... and 71 files with indirect coverage changes

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