tests: Bluetooth: mesh: Remove explicit disable of CSA#2

Remove explicit disable of Channel Selection Algorithm #2
in the mesh tests that use Extended Advertising.

Fixes zephyrproject-rtos#39188.

Signed-off-by: Vinayak Kariappa Chettimada <[email protected]>

Author: cvinayak

tests/bluetooth/mesh/ext_adv.conf

@@ -10,7 +10,6 @@ CONFIG_BT_CTLR_LE_ENC=n
 CONFIG_BT_CTLR_LE_PING=n
 CONFIG_BT_DATA_LEN_UPDATE=n
 CONFIG_BT_PHY_UPDATE=n
-CONFIG_BT_CTLR_CHAN_SEL_2=n
 CONFIG_BT_CTLR_MIN_USED_CHAN=n
 CONFIG_BT_CTLR_PRIVACY=n