Fix the freeform task bounds changed after device reboot

The task bounds of the freeform task was not preserved to file
after resizd/moved. Then the device was rebooted, the same Task
was displayed in a different size when starting it from the Recents.

Bug: 378653316
Test: reboot device
Flag: EXEMPT bugfix
Change-Id: I2f14447ae919f8075de0d09559ea0a68ae26d503