Incorrect project-specific where clause

If user has access to only one project (or if there is only one project
in bug tracker), helper_project_specific_where() function returned an
incorrect where clause when $project_id == ALL_PROJECTS.

Fixes #17073
Localisation updates from https://translatewiki.net.
Localisation updates from https://translatewiki.net.
Fixes #17076: Issue history show date submitted and last updated as integers rather than dates.