Stop making unnecessary calls in Project Summary page

[magicznyleszek]

Checklist

1. If you've added code that should be tested, add tests
2. If you've changed APIs, update (or create!) the documentation
3. Ensure the tests pass
4. Make sure that your code lints and that you've followed our coding style
5. Write a title and, if necessary, a description of your work suitable for publishing in our release notes
6. Mention any related issues in this repository (as #ISSUE) and in other repositories (as kobotoolbox/other#ISSUE)
7. Open an issue in the docs if there are UI/UX changes

Description

Avoid making unnecessary calls for project with no submissions. Also don't show a "Not found" error for expected 404 response from API for the graph.

Notes

Things changed here:

• SubmissionsCountGraph component is making a call to counts API, a 404 will be returned when there are no counts for given period. We were unnecessarily displaying error notification for this
• Similarly FormSummaryProjectInfo is making a call to submissions API to display information about latest submission. We were unnecessarily making call knowing there are no submissions

[noliveleger]

LGTM