Fix how Framework.getProperty reads accentued characters

Since NXP-23741 the Nuxeo launcher decodes the configuration properties which impacts the value read by Framework.getProperty

Steps to reproduce:

1. add this line to nuxeo.conf (or any nuxeo.defaults)

   search.default.article.type.filter=Livre,Publicit\u00e9,S\u00e9rie ou h\u00e9ros,Sous-s\u00e9rie et h\u00e9ros
   

2. run "nuxeoctl configure"
3. open nxserver/config/configuration.properties and observe that the value has been decoded

   search.default.article.type.filter=Livre,Publicité,Série ou héros,Sous-série et héros
   

4. now run a little program (or put a breakpoint) where you'll read this property with Framework.getProperty

   Framework.getProperty("search.default.article.type.filter")
   

5. observe that a value with incorrect characters is

   Livre,Publicité,Série ou héros,Sous-série et héros

    

Expected behavior: Framework.getProperty returns the same value as the one in configuration.properties (or the decoded value from nuxeo.conf)