refine text decode (#657)

### What problem does this PR solve?
#651 

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

deepdoc/parser/excel_parser.py

 
         if fnm.split(".")[-1].lower() in ["csv", "txt"]:
             encoding = find_codec(binary)
-            txt = binary.decode(encoding)
+            txt = binary.decode(encoding, errors="ignore")
             return len(txt.split("\n"))
 
 

rag/app/book.py

         txt = ""
         if binary:
             encoding = find_codec(binary)
-            txt = binary.decode(encoding)
+            txt = binary.decode(encoding, errors="ignore")
         else:
             with open(filename, "r") as f:
                 while True:

rag/app/laws.py

         txt = ""
         if binary:
             encoding = find_codec(binary)
-            txt = binary.decode(encoding)
+            txt = binary.decode(encoding, errors="ignore")
         else:
             with open(filename, "r") as f:
                 while True:

rag/app/naive.py

         txt = ""
         if binary:
             encoding = find_codec(binary)
-            txt = binary.decode(encoding)
+            txt = binary.decode(encoding, errors="ignore")
         else:
             with open(filename, "r") as f:
                 while True:

rag/app/one.py

         txt = ""
         if binary:
             encoding = find_codec(binary)
-            txt = binary.decode(encoding)
+            txt = binary.decode(encoding, errors="ignore")
         else:
             with open(filename, "r") as f:
                 while True:

rag/app/qa.py

         txt = ""
         if binary:
             encoding = find_codec(binary)
-            txt = binary.decode(encoding)
+            txt = binary.decode(encoding, errors="ignore")
         else:
             with open(filename, "r") as f:
                 while True:

rag/app/table.py

         txt = ""
         if binary:
             encoding = find_codec(binary)
-            txt = binary.decode(encoding)
+            txt = binary.decode(encoding, errors="ignore")
         else:
             with open(filename, "r") as f:
                 while True: