Jira Macro Repair fails on macros with missing fields

Issue Summary

This is reproducible on Data Center: No

Steps to Reproduce

1. Migrate an old page which has a Jira macro missing either "server" or "serverId" parameter

Ex: 

<structured-macro ac:name="jira" ac:schema-version="1" ac:macro-id="6d8dda5b-b497-4848-80fe-79936222d7d8">
    <parameter ac:name="server">
        JIRA
    </parameter>
    <parameter ac:name="key">
        TEST-123
    </parameter>
</structured-macro> 

^ This Jira Macro is missing the "serverId" parameter. 

2. Run Jira Macro Repair
 

Expected Results

The Jira Macro is fixed or skipped gracefully. 

Actual Results

Jira Macro Repair errors out when it encounters this error and a log like this can be seen: 

java.lang.NullPointerException: Cannot invoke "String.trim()" because "server" is null 

Workaround

Contact Atlassian Support.