AccessorFindingExpressionVisitor doesn't handle soft casts (i.e. TypeAs expression) but works for hard cast (Convert expression)
Description
AccessorFindingExpressionVisitor fails if the searched expression is hidden behind soft cast.
E.g.
searched expression: [c]
fullExpression: [c] as MyBaseClass
doesn't find [c], but ConvertExpression is handled properly:
if fullExpression is:
(MyBaseClass)[c]
c is found without issue.
