isolatedDeclaration: dropping types used in declare module blocks

[yyx990803]

When using isolatedDeclaration transform:

In:

import { type X } from './x'

type Y = 1

declare module "foo" {
  interface Foo {
    x: X
    y: Y
  }
}

Out (see that import of X and declaration of Y are both incorrectly removed):

declare module "foo" {
	interface Foo {
		x: X;
		y: Y;
	}
}
export {};