Describe the bug
Three things are happening when typing in a store URL that doesn't exactly match the correct URL:

1. When typing www. at the beginning, If the url would usually redirect, after successfully signing in it takes you to the screen that says this site is connected to a different email
2. If I type http:// instead of https:// I get the same error as above
3. If the site doesn't exist when the www is included (there is no redirect), you receive an error that the url is not valid

To Reproduce
Steps to reproduce the behavior:

1. Go to the landing page
2. Click on 'Sign In'
3. Type in a url with the www. that would either usually redirect
4. Sign in with WP.com credentials linked to that site
5. See error

For the second scenario, you will make it to step 3 and then see the error

Expected behavior
I would expect the user to type in their url in different formats and still work. I wonder if we can strip out the www., http://, https:// before processing the url. In the original mockups there is permanent text for the https:// and a placeholder for the url to help the user know what to type in here:

cc @AmandaRiu

Isolating the problem (mark completed items with an [x]):

• I have deactivated other plugins and confirmed this bug occurs when only WooCommerce plugin is active.
• This bug happens with a default WordPress theme active, or Storefront.
• I can reproduce this bug consistently using the steps above.