opentelemetry-instrumentation-logging: don't add out of spec attributes by default (#4112)

* opentelemetry-instrumentation-logging: don't add out of spec attributes by default

Add span context attributes to logging module LogRecord only if the instrumentation
has been configured to do so via set_logging_format argument or OTEL_PYTHON_LOG_CORRELATION
environment variable.

* Add changelog

* Update doc and cleanup tests

* Reduce diff

* Add missing test