XWIKI-11528: Office viewer fails if the page where the file is attached has a special character in the name (whitespace)
* There's no need to double encode the file path because the 'temp' action uses it as is to access the temporary file. Moreover the double encoding seems to cause problems when mode_proxy is used (with 'nocanon' option disabled).

(cherry picked from commit 35a33b1463bc0eccf02ed54ff9d1ca73ac123f7c)