Nope. Painter's Servant can only affect cards in one of the game zones. It will not affect cards outside of the game, like the sideboard. The cards in your sideboard are not affected by the Servant's ability, and you could not use Glittering Wish to get the Stony Silence out of your sideboard.
400.10a Cards in a player’s sideboard are outside the game. See rule 100.4.
400.10c Cards outside the game can’t be affected by spells or abilities, except for characteristic-defining abilities printed on them (see rule 604.3) and spells and abilities that allow those cards to be brought into the game.
Nathan Long
Magic Rules NetRep