[BE] Home page in EM sitemap is marked as "/" in some channels

In most channels the root element of the sitemap is named "root" but in HAP, HAP sub and React CSR SPA it's just a "/".

It makes these tests fail:
Test / Test (HAP community) / Channel Manager page actions Part1.user creates and deletes page without publishing
Test / Test (HAP community) / Channel Manager page actions Part1.user creates and deletes page with publishing
Test / Test (HAP community) / Channel Manager page actions Part1.user creates and deletes nested pages - without publishing

They are disabled and marked with this JIRA issue so you can easily find them and use for fix verification. Please also enable them once the fix is available before you merge.