Fix: Do not combine default type imports with value imports

[IanVS]

This fixes a bug which was causing default type imports to be combined into value imports, which isn't safe to do. For instance,

import { ComponentProps, useEffect } from 'react';
import type React from 'react';

was turning into

import { ComponentProps, useEffect, React } from 'react';

Which is not correct. This change prevents default type imports from ever being merged.

[IanVS]

I'm going to merge this to get the fix released, but I'd still love an ex post facto review if anyone has some time.

[fbartho]

Looks great @IanVS, good catch!