SDS email notifications should use Customer Portal URL instead of JIRA's Base URL

Summary

Currently, it's not possible to have a different Customer Portal URL from JIRA's Base URL without customizations:

• Make it possible to use service desk in combination with subdomains
• Create ability to customize the Customer Portal URL in JIRA ServiceDesk

Even when customizations are done, SDS email notifications still use JIRA's Base URL instead of the customized Portal URL, causing confusion to customers (especially those without access to JIRA's Base URL).

Suggestion

When implementing the above 2 features, take into account the usage of Portal URL in SDS email notifications.