chore(telemetry): revert enable telemetry by default (backport #3983) (#3985)

This is an automatic backport of pull request #3983 done by [Mergify](https://mergify.com).


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Author: mergify[bot]

ddtrace/bootstrap/sitecustomize.py

@@ -119,7 +119,7 @@ def update_patched_modules():
 
     # instrumentation telemetry writer should be enabled/started after the global tracer and configs
     # are initialized
-    if asbool(os.getenv("DD_INSTRUMENTATION_TELEMETRY_ENABLED", True)):
+    if asbool(os.getenv("DD_INSTRUMENTATION_TELEMETRY_ENABLED")):
         telemetry_writer.enable()
 
     # Check for and import any sitecustomize that would have normally been used

docs/configuration.rst

@@ -64,12 +64,6 @@ below:
      - Enable sending of spans to the Agent. Note that instrumentation will still be installed and spans will be
        generated. Added in ``v0.41.0`` (formerly named ``DATADOG_TRACE_ENABLED``).
 
-       .. _dd-instrumentation-telemetry-enabled:
-   * - ``DD_INSTRUMENTATION_TELEMETRY_ENABLED``
-     - Boolean
-     - True
-     - Enables sending telemetry events to the agent.
-
        .. _dd-trace-debug:
    * - ``DD_TRACE_DEBUG``
      - Boolean