ci: set CMAKE_BUILD_PARALLEL_LEVEL for mac builds (#11863)

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
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[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

.github/workflows/build_python_3.yml

@@ -132,6 +132,10 @@ jobs:
           CIBW_BEFORE_ALL_WINDOWS: rustup target add i686-pc-windows-msvc
           CIBW_BEFORE_ALL_MACOS: rustup target add aarch64-apple-darwin
           CIBW_ENVIRONMENT_LINUX: PATH=$HOME/.cargo/bin:$PATH CMAKE_BUILD_PARALLEL_LEVEL=24
+          # SYSTEM_VERSION_COMPAT is a workaround for versioning issue, a.k.a.
+          # `platform.mac_ver()` reports incorrect MacOS version at 11.0
+          # See: https://stackoverflow.com/a/65402241
+          CIBW_ENVIRONMENT_MACOS: CMAKE_BUILD_PARALLEL_LEVEL=24 SYSTEM_VERSION_COMPAT=0
           CIBW_REPAIR_WHEEL_COMMAND_LINUX: |
             mkdir ./tempwheelhouse &&
             unzip -l {wheel} | grep '\.so' &&

pyproject.toml

@@ -204,12 +204,6 @@ test-command = ["python {project}/tests/smoke_test.py"]
 # Skip trying to test arm64 builds on Intel Macs
 test-skip = "*-macosx_universal2:arm64"
 
-[tool.cibuildwheel.macos.environment]
-# Workaround for Macos 11.0 versioning issue, a.k.a.
-# `platform.mac_ver()` reports incorrect MacOS version at 11.0
-# See: https://stackoverflow.com/a/65402241
-SYSTEM_VERSION_COMPAT = "0"
-
 [tool.ruff]
 exclude = [
     ".riot",