Floss: Fix btm_find_dev_with_lenc to use correct callback

The list_foreach function within btm_find_dev_with_lenc will return
the first node for which the callback function returns FALSE.
Negate the callback function to fix it.

Bug: 269821708
Test: Pair with FP capable LE Audio earbuds while other set is already
      paired
Change-Id: I01af51b0ed6cf4a220556161f3d5ab24dce3f1fe