packageTheme doesn't strip 'dist' from file references in JS files

[tksheppard]

Describe the bug

If you are using a direct file reference in your JS, for your dev environment you need dist/ included as that's where the temp output resides. When you packageTheme, this is all removed and the files and folders move up into the root. This is generally managed by a line of code that strips dist/ out of all file references in .ascx files. However, any references in JS files remain pointing to dist/.

To Reproduce

Steps to reproduce the behavior:

1. Have a JS file that references another file.
2. gulp packageTheme
3. Check output JS file and see that the file reference still points to dist/.

Expected behavior

Any file references in JS that include dist/ should be stripped of it when the theme is packaged. This should not change the file itself, or what is in the dist folder for a regular gulp build--only the output in the theme package.