tools/mgmt-tester: Adds new test data with updated tx power

tools/mgmt-tester: Adds new test data with updated tx power

This patch adds new test data for the ext advertising test cases that
presets the advertising parameter and toggles the connectable flags.

When the adv instance is created, it updates the default tx power with
the value read from the controller. After toggling the connectable flag,
the host uses the tx_power stored in the adv list cache, which is the
value read from the controller, instead of the default tx power
value(127).

Signed-off-by: Anuj Jain <anuj01.jain@samsung.com>
Signed-off-by: Ayush Garg <ayush.garg@samsung.com>