CoapServer: fix bug in endpoints_to_string_list_filtered()

- the creation of the response only worked for the first endpoint
of the resource directory.

the fix now allows to return the complete list of all endpoints of a server.

Signed-off-by: Jacopo Zorzetto <jacopo.zorzetto@mail.polimi.it>
4 jobs for !23 with virt_mr
merge request