MediaMetrics: Fix inaccurate attribution of thread device

CreatePatch metric was overwriting the input and output device
before endIntervalGroup was called.

Use a separate last device field to send the device associated with
the endIntervalGroup.

Fix an issue with multiple devices that the '|' was not embedded
in the device string.

Test: adb shell dumpsys media.metrics
Bug: 247029889
Bug: 247907183
Change-Id: I659d9643782ff03ce5b196cce9f2e9d09c4e609c