Adapt project controller specs to Bootstrap

The project#index, and project#subprojects were migrated to DataTables
and therefore, the previous specs didn't make sense anymore. These need
to be feature specs.

The "clear_failed_comment" spec for the "js" format was testing that the
flash message was displayed. This is a feature spec.

Refresh cassettes.

Co-authored-by: Dany Marcoux <dmarcoux@suse.com>