Add auto-completion flash lite support for Gemini 2.5 Flash Lite testing (#3453)

original PR with approval: https://github.com/Skyvern-AI/skyvern-cloud/pull/6309

skyvern/forge/app.py

@@ -83,6 +83,11 @@ CHECK_USER_GOAL_LLM_API_HANDLER = (
     if SETTINGS_MANAGER.CHECK_USER_GOAL_LLM_KEY
     else SECONDARY_LLM_API_HANDLER
 )
+AUTO_COMPLETION_LLM_API_HANDLER = (
+    LLMAPIHandlerFactory.get_llm_api_handler(SETTINGS_MANAGER.AUTO_COMPLETION_LLM_KEY)
+    if SETTINGS_MANAGER.AUTO_COMPLETION_LLM_KEY
+    else SECONDARY_LLM_API_HANDLER
+)
 SVG_CSS_CONVERTER_LLM_API_HANDLER = SECONDARY_LLM_API_HANDLER if SETTINGS_MANAGER.SECONDARY_LLM_KEY else None
 
 WORKFLOW_CONTEXT_MANAGER = WorkflowContextManager()