Correctly handle projects without config on release_notification

Closes https://gitlab.com/dependabot-gitlab/dependabot/-/issues/211

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Allure report

allure-report-publisher generated test report!

rspec: ✅ test report for 06fcb6a1

+------------------------------------------------------------------+
|                        behaviors summary                         |
+-------------+--------+--------+---------+-------+-------+--------+
|             | passed | failed | skipped | flaky | total | result |
+-------------+--------+--------+---------+-------+-------+--------+
| controllers | 24     | 0      | 0       | 0     | 24    | ✅     |
| services    | 165    | 0      | 0       | 0     | 165   | ✅     |
| models      | 3      | 0      | 0       | 0     | 3     | ✅     |
| jobs        | 14     | 0      | 0       | 0     | 14    | ✅     |
| system      | 9      | 0      | 0       | 0     | 9     | ✅     |
| tasks       | 8      | 0      | 0       | 0     | 8     | ✅     |
+-------------+--------+--------+---------+-------+-------+--------+
| Total       | 223    | 0      | 0       | 0     | 223   | ✅     |
+-------------+--------+--------+---------+-------+-------+--------+