fixup! Reorder requirements file decoding

Author: matthewhughes934

src/pip/_internal/req/req_file.py

@@ -600,11 +600,11 @@ def _decode_req_file(data: bytes, url: str) -> str:
             return data[len(bom) :].decode(encoding)
 
     for line in data.split(b"\n")[:2]:
-        if line[0:1] == b"#" and PEP263_ENCODING_RE.search(line):
+        if line[0:1] == b"#":
             result = PEP263_ENCODING_RE.search(line)
-            assert result is not None
-            encoding = result.groups()[0].decode("ascii")
-            return data.decode(encoding)
+            if result is not None:
+                encoding = result.groups()[0].decode("ascii")
+                return data.decode(encoding)
 
     try:
         return data.decode(DEFAULT_ENCODING)