[power][SAG] Add AcquireLongWakeLease

Add this API to distinguish long wake lease from short ones.

Bug: b/491854803
Test: CQ
  fx test //src/power/system-activity-governor \
    --test-filter=*acquire_long_wake_lease*

Change-Id: I305f85a7f6b6167e71bae0b85454c580a3e5e72e
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1556214
Commit-Queue: Hai Bi <bihai@google.com>
API-Review: Michael Brunson <mbrunson@google.com>
Reviewed-by: Onath Dillinger <claridge@google.com>
Reviewed-by: Ruby Zhuang <rdzhuang@google.com>
Reviewed-by: Michael Brunson <mbrunson@google.com>