Avoid camera switch while HDR activation is in progress (camera-haleakala)

Avoid camera switch while HDR activation is in progress (camera-haleakala)

- Adding pre-change listener to MultiToggleImageButton to be executed before running state change animations
- Allowing button initialization with pre-change callback in ButtonManager
- Adding pre-change callback for conflicting options in CameraAppUI:
   HDR/HDR+ button disables camera button to avoid camera facing switch
   Camera facing disables HDR/HDR+
- Conflicting button is shown in disabled state for a while until re-enabled if applicable when the module switch is completed

Bug: 20696068
Change-Id: I11a0a0567363f656be52a9ece0707ccf326f2d67