Exclude time spent with emulator paused from play time

With this change, the play time reported internally by a game's gameplay timer should match (or be much closer to matching) what Ryujinx displays in the application library.

Aside from this being closer to the natural expectation of what "hours played" would take into account (as by definition time spent paused is time spent not playing), this also brings us closer to the behavior of other emulators and game libraries.