Fix Calendar Properties URLs Are Missing a Slash (#7235)

# Description & Issue number it closes
Fix Calendar Properties URLs Are Missing a Slash
Issue: 7234

## Screenshots (if appropriate)
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## How to test the changes?

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] This change requires a documentation update

# How Has This Been Tested?

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# Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

src/skin/js/Calendar.js

@@ -97,16 +97,16 @@ window.calendarPropertiesModal = {
         if (calendar.AccessToken) {
             HTMLURL =
                 window.CRM.fullURL +
-                "external/calendars/" +
+                "/external/calendars/" +
                 calendar.AccessToken;
             icsURL =
                 window.CRM.fullURL +
-                "api/public/calendar/" +
+                "/api/public/calendar/" +
                 calendar.AccessToken +
                 "/ics";
             jsonURL =
                 window.CRM.fullURL +
-                "api/public/calendar/" +
+                "/api/public/calendar/" +
                 calendar.AccessToken +
                 "/events";
         }