applications: nrf5340_audio: Set conn to NULL for bt_conn_le_create()

After zephyrproject-rtos/zephyr#79856
a warning message is printed out if the connection object is not
initialized to NULL.

This commit addresses this by initialing it.

Signed-off-by: Rubin Gerritsen <[email protected]>
(cherry picked from commit 9ad182c)

Author: rugeGerritsen

applications/nrf5340_audio/src/bluetooth/bt_management/scanning/bt_mgmt_scan_for_conn.c

@@ -43,7 +43,7 @@ static void bond_connect(const struct bt_bond_info *bond_info, void *user_data)
 {
 	int ret;
 	const bt_addr_le_t *adv_addr = user_data;
-	struct bt_conn *conn;
+	struct bt_conn *conn = NULL;
 	char addr_string[BT_ADDR_LE_STR_LEN];
 
 	if (!bt_addr_le_cmp(&bond_info->addr, adv_addr)) {
@@ -137,7 +137,7 @@ static bool device_name_check(struct bt_data *data, void *user_data)
 {
 	int ret;
 	bt_addr_le_t *addr = user_data;
-	struct bt_conn *conn;
+	struct bt_conn *conn = NULL;
 	char addr_string[BT_ADDR_LE_STR_LEN];
 
 	/* We only care about LTVs with name */
@@ -197,7 +197,7 @@ static bool csip_found(struct bt_data *data, void *user_data)
 {
 	int ret;
 	bt_addr_le_t *addr = user_data;
-	struct bt_conn *conn;
+	struct bt_conn *conn = NULL;
 	char addr_string[BT_ADDR_LE_STR_LEN];
 
 	if (!bt_csip_set_coordinator_is_set_member(server_sirk, data)) {