[Maya] broken image plane workaround

Sometimes the image plane just stops showing up in the viewports which can be really frustrating. Not exactly sure what causes it, but it seems to happen on cameras with multiple sub groups when using the mia_exposure_simple lens shader.
If adjusting the near/far clip plane doesnt fix it, the camera is probably broken.

Heres a workaround:
1) Create a new camera
2) Copy all settings from old to new camera
3) Constrain point/orient from old to new
4) Bake keys, delete constraints
5) Create a new image plane
6) Lastly add mia_exposure_simple

-- This basically clones the bad cameras attributes onto a working one