fix(ddtrace/tracer): Disable agent features and remote configuration in CI Visibility agentless mode

[tonyredondo]

What does this PR do?

This PR disables the agent features request and the remote configuration if the tracer was loaded in CI Visibility agentless mode.

v2: #3027

Ticket: SDTEST-1321

Motivation

In agentless mode we don't use an agent so those features are not available.

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.
• For internal contributors, a matching PR should be created to the v2-dev branch and reviewed by @DataDog/apm-go.

Unsure? Have a question? Request a review!

[datadog-datadog-prod-us1]

Datadog Report

Branch report: tony/civisibility-improve-startup
Commit report: da5dd7a
Test service: dd-trace-go

✅ 0 Failed, 5108 Passed, 67 Skipped, 2m 26.11s Total Time

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-12-10 22:52:28

Comparing candidate commit 14677a3 in PR branch tony/civisibility-improve-startup with baseline commit a48a41e in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 59 metrics, 0 unstable metrics.