wifi: shell: removed NULL check to net_mgmt callback

Since PR, PR_SHELL, PR_ERROR, PR_INFO, and PR_WARNING already have
an embedded `sh` NULL check, we can remove the change from PR #68809.

Signed-off-by: Pisit Sawangvonganan <pisit@ndrsolution.com>
(cherry picked from commit b6f51edd6c171996fc35c43f595c7047a3d38cf8)
diff --git a/subsys/net/l2/wifi/wifi_shell.c b/subsys/net/l2/wifi/wifi_shell.c
index 1a924c3..9d869fb 100644
--- a/subsys/net/l2/wifi/wifi_shell.c
+++ b/subsys/net/l2/wifi/wifi_shell.c
@@ -404,10 +404,6 @@
 static void wifi_mgmt_event_handler(struct net_mgmt_event_callback *cb,
 				    uint32_t mgmt_event, struct net_if *iface)
 {
-	if (context.sh == NULL) {
-		return;
-	}
-
 	switch (mgmt_event) {
 	case NET_EVENT_WIFI_SCAN_RESULT:
 		handle_wifi_scan_result(cb);