selftests: mptcp: connect: fix misaligned output

The first [ OK ] in the output of mptcp_connect.sh misaligns with the
others:

New MPTCP socket can be blocked via sysctl              [ OK ]
INFO: validating network environment with pings
INFO: Using loss of 0.85% delay 16 ms reorder 95% 70% with delay 4ms on
ns1 MPTCP -> ns1 (10.0.1.1:10000      ) MPTCP   (duration   184ms) [ OK ]
ns1 MPTCP -> ns1 (10.0.1.1:10001      ) TCP     (duration    50ms) [ OK ]
ns1 TCP   -> ns1 (10.0.1.1:10002      ) MPTCP   (duration    55ms) [ OK ]

This patch aligns them by using 69 chars to display the first two lines,
and 50 chars for the other. Since 19 chars are used to display duration
time. Also print out a [ OK ] at the end of the 2nd line for consistency.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240308-upstream-net-next-20240308-selftests-mptcp-unification-v1-3-4f42c347b653@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>