Selecting the Jira Charts macro does not work for Confluence-only users in externally connected instances

Issue Summary

As part of the Jira integration with Confluence, users can use the Application links in order to connect both products and use macros like the Jira Charts one.

Although this macro can be used for externally connected (or if both products are automatically connected if they are under the same instance/URL) instances, if Confluence gets integrated with an external Jira and later, a Jira product is added to the instance, users that have Confluence-only access will not be able to use the macro.

Steps to Reproduce

1. Have a Confluence-only instance (without Jira added to it).
2. Integrate Confluence with an external Jira instance via Application links
3. Once the authentication is finished, add a Jira product to the instance. This will make both Confluence and the new Jira to be automatically connected.
4. Have a user without access to the added Jira editing a page and insert the Jira Charts macro

 Even if the external app links get removed, the macro will still not work if the user does not have access to Jira.

Expected Results

The macro should be added to retrieve information from Jira.

Actual Results

As soon as the macro is selected, it disappears, as if nothing happened. In the browser's console, the following error is displayed:

VM1001:1 Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0
    at JSON.parse (<anonymous>)
    at Object.error (batch.js?build-number=6452&externals=__local-default__&locale=en-US:3783)
    at n (1.7.2.1-confluence-custom-m07.js:1)
    at Object.fireWith [as rejectWith] (1.7.2.1-confluence-custom-m07.js:1)
    at T (1.7.2.1-confluence-custom-m07.js:1)
    at r (1.7.2.1-confluence-custom-m07.js:1)
    at Object.send (1.7.2.1-confluence-custom-m07.js:1)
    at Function.ajax (1.7.2.1-confluence-custom-m07.js:1)
    at Object.makeRequest (batch.js?build-number=6452&externals=__local-default__&locale=en-US:3437) 

Workaround

Grant the user with access to the newly added Jira instance through the User management