Fix various dt_diff issues recently introduced and bump Parthenon (for dn outputs)

[pgrete]

There were several subtle issues introduced in #124 that are now fixed:

• dt_diff was reset prior to the STS tasks being added at the end of the driver (resulting in incorrect values of dt_diff for those tasks.
  To fix this the task resetting dt_diff is now called in a region following AddSTSTasks
• dt_diff was used in AddSTSTasks in the code that adds tasks themselves (and not within a task).
  Therefore, the tasks syncing/reducing dt_diff were not executed yet resulting in each rank using it's rank local dt_diff.
  To fix this, the reduction "tasks" are now not tasks anymore but the reduction is called as PreStepUserMeshWork guaranteeing all info in sync before the task list is being constructed (and any tasks is executed).
• dt_diff and dt_hyp got the Mutability::Restart flag in Bump Kokkos 4.4.1, Parth vov-fix #124 causing issues when restarting an older sim that did not write these Params yet.
  Reading those is actually unnecessary with the move to reducing everything in PreStepUserMeshWork, so the Params are now just Mutable again and are not being read from the restart file.

Finally, I updated the Parthenon submodule to include the now merged Kokkos 4.4.1 view of view fix and also the approved changes for dn based outputs.