webremote: fix french mistranslation of "key"

Hi! The original french translation used the word "touche" (a keyboard's key/a button) to mean key but what was actually meant was "clé" (a door's key/a password)

For context: this mistranslation can be found inside the Web Remote plugin's settings and affects the "Access key:" string

It's my first time publishing an MR here so I don't know if there is anything else I'm supposed to do when submitting a patch. Feel free to tell me if I'm missing anything! :)