bluetooth: controller: Enable data length update in ctrl_collision test

The test expects this feature to be enabled.
We should therefore enable explicitly instead of relying on
default values.

Signed-off-by: Rubin Gerritsen <[email protected]>

Author: rugeGerritsen

tests/bluetooth/controller/ctrl_collision/prj.conf

@@ -27,5 +27,6 @@ CONFIG_BT_CTLR_SCA_UPDATE=y
 CONFIG_BT_SCA_UPDATE=y
 
 CONFIG_BT_PHY_UPDATE=y
+CONFIG_BT_DATA_LEN_UPDATE=y
 CONFIG_BT_CTLR_PHY_2M=y
 CONFIG_BT_CTLR_PHY_CODED=y