Jira count macro fails with an error when the jira server URL ends with a /

How to reproduce:

• in the administration of your wiki, using the JIRA administration application, configure a jira instance, and have the URL set there end with a /
• in a page, add a jira macro (any) to display issues from that jira server (using the jira id), with a jql
• the jira macro should display a listing of issues (based on the provided jql)
• add a jiraCount macro, with exactly the same parameters - same jira server and same jql

Expected result:

• the jiraCount macro should display the number of issues that were displayed in the listing of the jira macro with the same parameters

Actual result:

• the jiraCount macro displays an error, while the jira macro with the same parameters works fine:

I checked the URL listed in the error, and the culprit is the double slash in the Jira API URL that is used by jiraCount (I opened it in a new tab and without the double slash it works fine). Apparently, the jira macro does not have the same issue.