logs: address memory optimization review comments

- Add missing Context import.
- Apply memory optimization to SimpleLogRecordProcessor.
- Update BatchLogRecordProcessor to use Context() instead of None.

Author: ajuijas

opentelemetry-sdk/src/opentelemetry/sdk/_logs/_internal/export/__init__.py

@@ -26,6 +26,7 @@
 from opentelemetry.context import (
     _ON_EMIT_RECURSION_COUNT_KEY,
     _SUPPRESS_INSTRUMENTATION_KEY,
+    Context,
     attach,
     detach,
     get_value,
@@ -224,8 +225,13 @@ def on_emit(self, log_record: ReadWriteLogRecord):
                 if log_record.resource is not None
                 else Resource.create({})
             )
+            # Shallow copy the API log record to break the reference to the potentially large context
+            # while keeping the original context intact for other processors.
+            api_log_record = copy.copy(log_record.log_record)
+            api_log_record.context = Context()
+
             readable_log_record = ReadableLogRecord(
-                log_record=log_record.log_record,
+                log_record=api_log_record,
                 resource=resource,
                 instrumentation_scope=log_record.instrumentation_scope,
                 limits=log_record.limits,