Clarify DevicePowerPeakShift description

Replace "system" by "device", because we use both "system" and "device"
in the policy description which is confusing.

Bug: b:174061781
Change-Id: Idaecbd4c5fe88070e2eee31944a70304104ee51f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2557503Reviewed-by: Pavol Marko <pmarko@chromium.org>
Commit-Queue: Oleh Lamzin <lamzin@google.com>
Cr-Commit-Position: refs/heads/master@{#830591}

components/policy/resources/policy_templates.json

@@ -20428,7 +20428,7 @@
       'id': 538,
       'caption': '''Enable peak shift power management''',
       'tags': [],
-      'desc': '''Setting the policy to Enabled and setting <ph name="DEVICE_POWER_PEAK_SHIFT_BATTERY_THRESHOLD_POLICY_NAME">DevicePowerPeakShiftBatteryThreshold</ph> and <ph name="DEVICE_POWER_PEAK_SHIFT_DAY_CONFIG_POLICY_NAME">DevicePowerPeakShiftDayConfig</ph> keeps power peak shift on, if supported on the device. Power peak shift power management policy is a power-saving policy that minimizes alternating current usage during peak times. For each weekday, you can set a start and end time to run in power peak shift mode. As long as the battery stays above the threshold specified, during these times, the system runs from the battery (even if the alternating current is attached). After the specified end time, the system runs from alternating current (if attached), but won't charge the battery. The system will again function normally using alternating current and recharging the battery after the specified start time.
+      'desc': '''Setting the policy to Enabled and setting <ph name="DEVICE_POWER_PEAK_SHIFT_BATTERY_THRESHOLD_POLICY_NAME">DevicePowerPeakShiftBatteryThreshold</ph> and <ph name="DEVICE_POWER_PEAK_SHIFT_DAY_CONFIG_POLICY_NAME">DevicePowerPeakShiftDayConfig</ph> keeps power peak shift on, if supported on the device. Power peak shift power management policy is a power-saving policy that minimizes alternating current usage during peak times. For each weekday, you can set a start and end time to run in power peak shift mode. As long as the battery stays above the threshold specified, during these times, the device runs from the battery (even if the alternating current is attached). After the specified end time, the device runs from alternating current (if attached), but won't charge the battery. The device will again function normally using alternating current and recharging the battery after the specified start time.
 
       Setting the policy to Disabled keeps power peak shift off.