[keymgr_dpe, dv] Update `altert_handler_escalation_vseq.sv`

@rroth-lowrisc is already working on this.

Since Aug 3, 2026.

### Description

There are few lines of code `chip_sw_alert_handler_escalation_vseq.sv` that checks that `curr_key` and `prev_key` are not equal inside `keymgr`. We need to think if it makes sense to write something similar for `keymgr_dpe`. This also requires definition of `signal_probe_keymgr_key_state`, which is also commented out in `chip_if.sv`.