Disney Character Actor Claims She Was Fired for Posting as Snow White

3:41 PM PT -- Sources with direct knowledge tell TMZ ... Disney is very big on character integrity -- because keeping the magic alive with their guests and patrons is of the utmost importance to them, which is why they ended up getting rid of Sophia Dottir. In this particular situation, we're told the character integrity they value was broken -- so they had to do what they had to do. In terms of the rumors that…