Remove useless code and unused parameter

Parameter $p_can_report_only on layout_navbar_projects_list() and
layout_navbar_subproject_option_list() functions was copied from
print_project_option_list() as part of layout API's initial creation.

It was never used, and in fact, was not even operational.

Commit eb31eb35c1b6f2ddc601f45e0dac535c7bd6c67 removing a call to
check_disabled() which left unused variables and code linked to this
functionality.

This commit finalizes the cleanup operation by removing the useless
parameter and unused code.

Fixes 0025894