Move some constants to common (#11004)

### What problem does this PR solve?

As title.

### Type of change

- [x] Refactoring

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Signed-off-by: Jin Hai <haijin.chn@gmail.com>

deepdoc/parser/figure_parser.py

@@ -17,7 +17,7 @@ from concurrent.futures import ThreadPoolExecutor, as_completed
 
 from PIL import Image
 
-from api.db import LLMType
+from common.constants import LLMType
 from api.db.services.llm_service import LLMBundle
 from common.connection_utils import timeout
 from rag.app.picture import vision_llm_chunk as picture_vision_llm_chunk