Update not-started activities' scheduled time when reseting workflows

[yycptt]

Is your feature request related to a problem? Please describe.
Currently when reseting workflows, if there's a scheduled but not started activity in the workflow, the scheduled time for that activity will remain unchanged in the new workflow created by the reset operation. Since the workflow is newly created, the activity scheduled time should also be updated otherwise the activity will timeout early after reset.

Proposed Solution
temporalio/temporal#1502

• Note that the history event timestamp for ActivityTaskScheduled event can't be updated since it's persisted. But when describing the workflow, activity scheduled time is retrieved from mutable state, so it will have the updated time.
• When reseting workflow, a new activity task will be created and pushed to matching with the new schedule, so even if the previous one expired, the new one can be used to start the activity.
• Client side will use the time specified in the ScheduledTimeOfThisAttempt field which is the updated schedule time, not the one from history event.
• Activity timeout timer task will check mutable state to see if an activity really need to be timed out when it's processed so it won't timeout the activity unexpectedly.

Additional context
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