[LE Audio] Improve the reconnection performance by using direct connect parameters

Use the direct connect parameters for the background connect the LE Audio device
after receiving the Target Announcements advertising.

Bug: 273596634
Test: atest BleConnectionManager
Test: Manual, check the connection parameters
Change-Id: Ib49ba2cccc4c75e12a45cc3a24db052944b0b2d9