refactor(magic_pdf): update invalid character detection logic

- Uncomment detect_invalid_chars_by_pymupdf function call
- Comment out detect_invalid_chars function call

magic_pdf/filter/pdf_meta_scan.py

@@ -323,8 +323,8 @@ def get_language(doc: fitz.Document):
 
 def check_invalid_chars(pdf_bytes):
     """乱码检测."""
-    # return detect_invalid_chars_by_pymupdf(pdf_bytes)
-    return detect_invalid_chars(pdf_bytes)
+    return detect_invalid_chars_by_pymupdf(pdf_bytes)
+    # return detect_invalid_chars(pdf_bytes)
 
 
 def pdf_meta_scan(pdf_bytes: bytes):