BUGFIX: sanitize current page input

[Pingu501]

On paginated sites the currentPage is not sanitized result in thrown errors: Unsupported operand types: string * int.

You can see this in the wild as soon as paginated page urls get manipulated. Samples:

• https://www.neos.io/blog~p$5.html
• https://sandstorm.de/blog~p$_5.html

We see these errors frequently in logs and exceptions from bots trying to exploit this.

[markusguenther]

Thanks for the fix ❤️

[dlubitz]

Thank you for taking care. I left a question, as I couldn't test it myself atm.

[dlubitz]

Ok, I tested it quickly and it works as expected.

# this is also 1
currentPage = ${0 || 1}