Log link in fuzzer stats is wrong when fuzzer=libFuzzer (or other engine) and sorting by day.

[jonathanmetzman]

1. Go to https://oss-fuzz.com/fuzzer-stats?group_by=by-day&date_start=2021-02-25&date_end=2021-03-03&fuzzer=libFuzzer&job=libfuzzer_asan_valijson&project=valijson
2. Log link is https://oss-fuzz.com/gcs-redirect?path=gs%3A%2F%2Fvalijson-logs.clusterfuzz-external.appspot.com%2FlibFuzzer_valijson_fuzzer%2Flibfuzzer_asan_valijson
3. Should probably be: https://oss-fuzz.com/gcs-redirect?path=gs%3A%2F%2Fvalijson-logs.clusterfuzz-external.appspot.com

There's not really a good answer on what it should be. And this is a minor issue because one wouldn't see this broken link by default, one would have to do a query, but better to show the logs bucket then send users to an empty directory which makes it look like there are no logs.