Include's overlap check causes issues with ddtrace

[alejandrodnm]

In #38 the following code was moved down.

https://github.com/DataDog/envier/pull/38/files#diff-328fcc831dd05af9986a37698ee9efaf88254ada077ef48a999221e6fe0551a5L374-L381

The problem is that overlap is checked against the global values, instead of being scoped to namespace.

This causes an issue with ddtracer

https://github.com/DataDog/dd-trace-py/blob/50b335982edd0fc283efc8f416f7f4bb32548f04/ddtrace/settings/profiling.py#L415-L419

Because all the stacks have an enabled attribute.

  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/ddtrace/internal/telemetry/__init__.py", line 6, in <module>
    from .writer import TelemetryWriter
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/ddtrace/internal/module.py", line 295, in _exec_module
    self.loader.exec_module(module)
  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/_pytest/assertion/rewrite.py", line 184, in exec_module
    exec(co, module.__dict__)
  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/ddtrace/internal/telemetry/writer.py", line 27, in <module>
    from ...settings.profiling import config as prof_config
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/ddtrace/internal/module.py", line 295, in _exec_module
    self.loader.exec_module(module)
  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/_pytest/assertion/rewrite.py", line 184, in exec_module
    exec(co, module.__dict__)
  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/ddtrace/settings/profiling.py", line 415, in <module>
    ProfilingConfig.include(ProfilingConfigStack, namespace="stack")
  File "/Users/adn/dev/timescale/lambda-pg-vectorizer/.venv/lib/python3.12/site-packages/envier/env.py", line 422, in include
    raise ValueError("Configuration clashes detected: {}".format(overlap))
ValueError: Configuration clashes detected: {'enabled'}

[P403n1x87]

Thanks for reporting this. This was fixed in #39.