fix: Resolve issue with plain text files not having magic file info (#1564)

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## Description
Some plain text files dont have to have magic binary info on file type,
in case file type guess was not able to dedcude file type consider it
plain text

## Type of Change
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- [ ] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [ ] Code refactoring
- [ ] Performance improvement
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cognee/infrastructure/files/utils/guess_file_type.py

@@ -124,6 +124,12 @@ def guess_file_type(file: BinaryIO) -> filetype.Type:
     """
     file_type = filetype.guess(file)
 
+    # If file type could not be determined consider it a plain text file as they don't have magic number encoding
+    if file_type is None:
+        from filetype.types.base import Type
+
+        file_type = Type("text/plain", "txt")
+
     if file_type is None:
         raise FileTypeException(f"Unknown file detected: {file.name}.")