Refa: treat MinerU as an OCR model (#11849)

### What problem does this PR solve?

 Treat MinerU as an OCR model.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)
- [x] Refactoring

deepdoc/parser/pdf_parser.py

@@ -39,7 +39,6 @@ from sklearn.metrics import silhouette_score
 from common.file_utils import get_project_base_directory
 from common.misc_utils import pip_install_torch
 from deepdoc.vision import OCR, AscendLayoutRecognizer, LayoutRecognizer, Recognizer, TableStructureRecognizer
-from rag.app.picture import vision_llm_chunk as picture_vision_llm_chunk
 from rag.nlp import rag_tokenizer
 from rag.prompts.generator import vision_llm_describe_prompt
 from common import settings
@@ -1455,6 +1454,8 @@ class VisionParser(RAGFlowPdfParser):
             if pdf_page_num < start_page or pdf_page_num >= end_page:
                 continue
 
+            from rag.app.picture import vision_llm_chunk as picture_vision_llm_chunk
+
             text = picture_vision_llm_chunk(
                 binary=img_binary,
                 vision_model=self.vision_model,