Updated link in energy-grants-calculator

[floehopper]

Supersedes #1993.

Updated link in energy-grants-calculator

https://govuk.zendesk.com/agent/tickets/1163441

A redirect at the destination meant this was going to the cavity wall page.

Note from @floehopper:

• Regression test artefacts updated & checked
• Regression test checksums updated
• These changes were committed separately, because a lot of files had changed and I thought it was clearer to do this rather than amend the original commit.

Expected changes

• Example URL
  • Link to "Solid Wall insulation" has changed from http://www.energysavingtrust.org.uk/Insulation/Solid-wall-insulation to http://www.energysavingtrust.org.uk/domestic/solid-wall