Remove file extension checking

[zhengliw]

When storing a PDF in a named temporary file, it does not have any file extension indicating it's a PDF, but the content is still valid for parsing. When passing the path as a string, camelot would refuse to parse the PDF due to the missing file extension. I propose the following change:

diff --git a/camelot/handlers.py b/camelot/handlers.py
index 14e29dd..f4e2263 100644
--- a/camelot/handlers.py
+++ b/camelot/handlers.py
@@ -68,9 +68,6 @@ class PDFHandler:
             filepath = download_url(str(filepath))
         self.filepath: StrByteType | Path | str = filepath
 
-        if isinstance(filepath, str) and not filepath.lower().endswith(".pdf"):
-            raise NotImplementedError("File format not supported")
-
         if password is None:
             self.password = ""  # noqa: S105
         else:

As a workaround for now, I pass pathlib.Path("path_to_pdf") instead of the string directly, which bypasses the checking. Unless there is a good reason to keep the file extension check, I would like to PR this change. Thank you in advance!