Fix Tools::stripslashes()

[MathiasReker]

The use of function stripslashes() is forbidden; use Tools::stripslashes() instead

[litespeedtech]

Hi, Mreker,
I have run with validator too and knew this complaint. But if you read the code for Tools::stripslashes, the wrapper will behave differently than direct call. And for the purpose of our use: remove slashes from json encoded javascript which has esi:include, we have to use the original function. I have rewrite many other code to avoid validator complain for using Tools wrapper. But this one I cannot. Tools wrapper is mainly for requests processing from outside, while LSCPS is internally injection of esi:include and esi:inline, that enforcement does not apply to our case.
Therefore, I have to reject your pull request.
Thanks and hope you can help in other ways.
Lauren