fix(api): Disable SSE events truncation for service api (#27484)

Disable SSE events truncation for service api invocations to ensure backward compatibility.

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

api/tests/unit_tests/services/test_variable_truncator.py

@@ -21,6 +21,7 @@ from core.file.enums import FileTransferMethod, FileType
 from core.file.models import File
 from core.variables.segments import (
     ArrayFileSegment,
+    ArrayNumberSegment,
     ArraySegment,
     FileSegment,
     FloatSegment,
@@ -30,6 +31,7 @@ from core.variables.segments import (
     StringSegment,
 )
 from services.variable_truncator import (
+    DummyVariableTruncator,
     MaxDepthExceededError,
     TruncationResult,
     UnknownTypeError,
@@ -596,3 +598,32 @@ class TestIntegrationScenarios:
         truncated_mapping, truncated = truncator.truncate_variable_mapping(mapping)
         assert truncated is False
         assert truncated_mapping == mapping
+
+
+def test_dummy_variable_truncator_methods():
+    """Test DummyVariableTruncator methods work correctly."""
+    truncator = DummyVariableTruncator()
+
+    # Test truncate_variable_mapping
+    test_data: dict[str, Any] = {
+        "key1": "value1",
+        "key2": ["item1", "item2"],
+        "large_array": list(range(2000)),
+    }
+    result, is_truncated = truncator.truncate_variable_mapping(test_data)
+
+    assert result == test_data
+    assert not is_truncated
+
+    # Test truncate method
+    segment = StringSegment(value="test string")
+    result = truncator.truncate(segment)
+    assert isinstance(result, TruncationResult)
+    assert result.result == segment
+    assert result.truncated is False
+
+    segment = ArrayNumberSegment(value=list(range(2000)))
+    result = truncator.truncate(segment)
+    assert isinstance(result, TruncationResult)
+    assert result.result == segment
+    assert result.truncated is False