The value in the Manifest Url field in the add skill modal persists between adding multiple skills

[tdurnford]

Description

If you try to add a second skill right after you added the first, the Manifest Url field is populated with the previous skill's url.

Version

To Reproduce

Steps to reproduce the behavior:

1. Go to the 'Skills' page
2. Click the 'Connect to a new skill' button
3. Add a valid Skill Manifest Url - https://yuesuemailskill0207-gjvga67.azurewebsites.net/manifest/manifest-1.0.json
4. Click the 'Connect to a new skill' button again
5. Notice the 'Manifest url' field is already populated

Expected behavior

Screenshots