fix(tests): correct indentation in actor_loading.feature

Fixed Gherkin syntax error where the 'LLM actor without tools' scenario had
incorrect indentation (3 spaces instead of 2), which prevented the feature
file from being parsed correctly by Behave. This was causing the concurrency
test scenario to fail during test discovery.

ISSUES CLOSED: #8588

features/actor_loading.feature

@@ -242,17 +242,17 @@ Feature: Actor registry and loader
     Given a temporary actors directory with a list-content YAML file "list.yaml"
     When I create an actor loader with that directory as search root
     And I run discovery expecting errors
-    Then the loader should raise a validation error mentioning "list.yaml"
+     Then the loader should raise a validation error mentioning "list.yaml"
 
-   Scenario: LLM actor without tools does not produce warnings with tool registry
-     Given a tool registry with tool "files/read_file"
-     And a temporary actors directory with files
-       | filename       | name                | type | model  |
-       | simple.yaml    | assistants/simple   | llm  | gpt-4  |
-     When I create an actor loader with that directory and the tool registry
-     And I run discovery
-     Then the loader should contain actor "assistants/simple"
-     And the loader should have 0 warnings
+  Scenario: LLM actor without tools does not produce warnings with tool registry
+    Given a tool registry with tool "files/read_file"
+    And a temporary actors directory with files
+      | filename       | name                | type | model  |
+      | simple.yaml    | assistants/simple   | llm  | gpt-4  |
+    When I create an actor loader with that directory and the tool registry
+    And I run discovery
+    Then the loader should contain actor "assistants/simple"
+    And the loader should have 0 warnings
 
   # ────────────────────────────────────────────────────────
   # Concurrency and race conditions