[dv/scb] Fix alert unexpected ping faliures
[dv/scb] Fix alert unexpected ping faliures

This PR fixes the regression error from alert_test:
```
UVM_ERROR @ 3371.559689 us: (cip_base_scoreboard.sv:200) uvm_test_top.env.scoreboard [uvm_test_top.env.scoreboard] alert lc_ctrl_fatal_prog_error has unexpected alert ping response
```

This check is not necessary because:
1). In chip level, having alert/esc ping from the background is normal
  and expected, should not flag an error
2). We cannot accurately predict when we are expecting a ping request,
  so there is no need to add this checking in chip level scb.

Signed-off-by: Cindy Chen <399ad771a111eac8923348b1e2af093034e5d4f1@opentitan.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan