Merge pull request #12688 from dorDiogo/isis_hello_padding_sometimes

isisd: Add support for IS-IS hello padding during-adjacency-formation

diff --cc doc/user/isisd.rst
Simple merge

diff --cc isisd/isis_circuit.c
Simple merge

diff --cc isisd/isis_cli.c
Simple merge

diff --cc isisd/isis_nb_config.c
Simple merge

diff --cc yang/frr-isisd.yang
Simple merge