IMCF Icons breaks when Application Link doesn't match Jira's Base url

Issue Summary

When you set up the application link between Confluence and Jira Service Management, and use this application link for the Insight Macros app in Confluence if the base URL of Jira doesn't match the application link URL, the icons of the table breaks.

Steps to Reproduce

1. Deploy Jira and Confluence
2. Integrate both through Application Links
3. Add the Insight Macro to a Confluence page
4. Change Jira's base URL and don't update the reciprocal application link URL in Confluence

Expected Results

The icons are properly displayed on the page.

Actual Results

The macros work as expected, but the icon breaks. The app tries to append both URLs in Jira's side, which uses the 'jira-proxy' tool of the plugin.

Any differences between the base URL and the application link base URLs are appended, for example below:

A stack trace is logged when accessing the icon URL where we can clearly see the URLs being appended:

<status-code>500</status-code>
<message>Refusing to sign non-normalized URL: http://jiraservicedesk:8831/j831http://localhost:8831/j831/rest/insight/1.0/objecttype/2/icon.png?size=48</message>
<stack-trace>java.lang.IllegalArgumentException: Refusing to sign non-normalized URL: http://jiraservicedesk:8831/j831http://localhost:8831/j831/rest/insight/1.0/objecttype/2/icon.png?size=48 at

Workaround

Set both Jira base URL and the application link URL to be the same.