trigger_camera doesn't restore its control over the player's view

[SamVanheer]

Saving and loading while the player is under the control of a trigger_camera results in the player's view not restoring to the one set by the camera. This breaks any camera-based scripted events set up in custom maps and mods.

This can be fixed by making the player track the view entity being used and restoring it on load.

Here's how i fixed it:
twhl-community/halflife-updated@5fd0acb

Note that this change could break backwards compatibility with older save games. It should definitely be fixed in SDK code, but it should be tested against older save games before applying the fix to official games.