WIP: contrib/google.golang.org/grpc: trace grpc encoding

[rarguelloF]

What does this PR do?

Motivation

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[bot]]

Benchmarks

Benchmark execution time: 2024-10-31 16:54:21

Comparing candidate commit 3081731eabebd22e0ab58405111e8463a3df979d in PR branch rarguelloF/trace-grpc-encoding with baseline commit 3cb8ab2a4c172bc5af3542608595198cb4cef3df in branch main.

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

scenario:BenchmarkTracerAddSpans-24

• 🟥 execution_time [+87.268ns; +137.932ns] or [+2.230%; +3.525%]