R1:10ef973735b2

Allow older, invalid project tags to continue to function

Summary:
Ref T10168.

Around October 12, T9551 made project hashtags stricter and prevented them from containing characters like comma (`,`).

Around December 27, D14888 changed how hashtags queries work so that the query does normalization instead of requiring the caller to normalize.

After the Dec 27 change, projects from before Oct 12 with now-invalid hashtags will no longer load when queried directly by hashtag, because the page queries for…