Fixed Junos reboots not being detected when waiting for the device to reload

[Defiantearth]

NAPPS-1176

What's Changed

• Updated the Juniper uptime property to refresh the device facts when _uptime is None, so it returns the live uptime instead of a stale cached value.
• Updated _wait_for_device_reboot to capture the pre-reboot uptime, close the connection, then poll every 10 seconds and treat the device as rebooted once the new uptime is lower than the original.
• Increased timeout from 3600 to 7200 seconds

Screenshot of OS Upgrades failing after Install OS because it did not wait for reboot correctly(Before).

Screenshot of OS Upgrades working Successfully(After).

To Do

• Explanation of Change(s)
• Added change log fragment(s) (for more information see the documentation)
• Attached Screenshots, Payload Example
• Unit, Integration Tests
• Documentation Updates (when adding/changing features)
• Outline Remaining Work, Constraints from Design

[Pkawa-ntc]

Please check my nitpicks, other than them, LGTM.