selftests/bpf: Exercise SOCK_STREAM unix_inet_redir_to_connected()

Constants got switched reducing the test's coverage. Replace SOCK_DGRAM
with SOCK_STREAM in one of unix_inet_skb_redir_to_connected() tests.

Fixes: 51354f70 ("bpf, sockmap: Add af_unix test with both sockets in map")
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Tested-by: Jakub Sitnicki <jakub@cloudflare.com>
Suggested-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Link: https://lore.kernel.org/r/20240731-selftest-sockmap-fixes-v2-5-08a0c73abed2@rbox.co


Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>