[nrf fromtree] test: bluetooth: mesh_shell: Remove setting BT_MAX_CONN

Only 1 connection is needed with default setting of mesh_shell.

Signed-off-by: Pavel Vasilyev <[email protected]>
(cherry picked from commit 8fdec22)

Author: PavelVPV

tests/bluetooth/mesh_shell/prj.conf

@@ -22,7 +22,6 @@ CONFIG_BT_PERIPHERAL=y
 CONFIG_BT_TINYCRYPT_ECC=y
 CONFIG_BT_DEVICE_NAME="Zephyr Mesh"
 CONFIG_BT_GATT_CACHING=n
-CONFIG_BT_MAX_CONN=2
 
 CONFIG_BT_CTLR_DUP_FILTER_LEN=0
 CONFIG_BT_CTLR_LE_ENC=n