[Misdetection] pptx file misdetected as xlsb

**What should the file have been detected as? What has the file been misdetected as?**
PPTX files are being mistaken as XLSB binary workbooks.

**Please link or attach the misdetected file below** (Do NOT upload PII!)
Will attempt to get a scrubbed/non-sensitive reproduction file put together.

**Additional context**

Versions impacted:
- 1.0.1 (python)
- 1.0.0 (node)
- 0.6.3 (python)

Methods used:
- Python
- nodejs

Parameters:
- each prediction mode
- local file and file stream

The payload names no source file, test, or reproduction file. Start by obtaining the promised scrubbed PPTX and reproduce the prediction through the Python and Node.js methods in each prediction mode; done means the PPTX is detected as PPTX rather than XLSB across the reported versions.

Written by the indexing model from the issue text.