fix(LongUrlEditor): strip protocol from long URL

[zwliew]

Problem

When editing the long URL in LongUrlEditor, the protocol is not automatically stripped. This behaviour does not match that of the link creation modal.

Closes #1092

Solution

Bug Fixes:

• Strip the protocol from the long URL before updating the state of the LongUrlEditor.

Tests

Protocol should be stripped when editing the long URL in LongUrlEditor:

1. Deploy the change
2. Change the long URL of an existing link to one prefixed with http:// or https://
3. The prefix should be automatically stripped

[LoneRifle]

lgtm