Add Nearby Share stress test

1) Add Nearby Share stress test
2) Refactor existing codes by removing the prefix of first_/sencond_ as much as possible to avoid the confusion to Nearby Share and eSIM transfer test which only needs one connection.
3) Rename esim_transfer_only_stress_test to esim_trasfer_stress_test.

Bug: 308484461
Test: manual
Change-Id: Ie68238a3588e990f05da83d6f92b837fef209265
9 files changed