Invalid URI: The hostname could not be parsed

[DmitryKolinchuk]

Description:
The issue occurs in CmIdentityServerSiteNameValidator.

Scenario:

1. Install Sitecore 10.1 that has the following site name:
   sc101r005862 (WDP XP0 packages)
2. Make sure that the "Validate" checkbox is checked.
3. Check Validation details.

Result: there is the following error:

Expected result: there are no errors.
Notes:
The issue happens because URL is not encoded: