chore: lazy load internal request module

[duncanista]

What does this PR do?

Reduces memory allocation for this package by lazy loading internal request.ts methods.

Before:

After:

Motivation

It was possible to reduce the memory allocations + performance.

Testing Guidelines

• Integration tests remained the same.
• Unit tests passed as normal
• Memory allocation was reduced.

Additional Notes

SVLS-4628

Allocation time can vary, but now we are sure that the lazy load is in effect.

Types of Changes

• [ ] Bug fix
• [ ] New feature
• [ ] Breaking change
• [x] Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• [ ] This PR's description is comprehensive
• [ ] This PR contains breaking changes that are documented in the description
• [ ] This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• [ ] This PR impacts documentation, and it has been updated (or a ticket has been logged)
• [ ] This PR's changes are covered by the automated tests
• [ ] This PR collects user input/sensitive content into Datadog
• [ ] This PR passes the integration tests (ask a Datadog member to run the tests)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 89.28571% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 81.90%. Comparing base (e08ad86) to head (a1247d1).

:exclamation: Current head a1247d1 differs from pull request most recent head 6cc0816. Consider uploading reports for the commit 6cc0816 to get more accurate results

Files	Patch %	Lines
src/metrics/listener.ts	87.50%	2 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #519 +/- ## ========================================== - Coverage 81.95% 81.90% -0.06% ========================================== Files 54 54 Lines 2206 2205 -1 Branches 512 513 +1 ========================================== - Hits 1808 1806 -2 + Misses 334 333 -1 - Partials 64 66 +2 ```

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