feat: PaddleOCR PDF parser supports thumnails and positions (#12565)

### What problem does this PR solve?

1. PaddleOCR PDF parser supports thumnails and positions.
2. Add FAQ documentation for PaddleOCR PDF parser.


### Type of change

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

web/src/pages/user-setting/setting-model/modal/paddleocr-modal/index.tsx

@@ -122,7 +122,7 @@ const PaddleOCRModal = ({
                 disabled={loading}
                 className="btn btn-primary"
               >
-                {loading ? t('common.adding') : t('common.add')}
+                {t('common.add')}
               </button>
             </div>
           </form>