Global merge request search won't find merge requests unless it is in user namespace

Steps to reproduce

1. Create a group
2. Add the user to the group as a maintainer
3. Create a project in that group
4. Create a merge request in that project titled "searchable mergerequest"
5. Perform a global search as the user who is a maintainer of that group for merge requests with the search string searchable
6. You will not see that merge request

Other notes

When performing the query against Elasticsearch it seems to only include the project ids that are part of the user's personal namespace and does not include groups the user is a member of.