Update permission strings

[tangobravo]

Use an empty string rather than "Not Used" for camera - the Zapbox SDK fills in a default if this is unset.

Add a descriptive permission string for microphone usage.

The microphone one in particular will likely come up in app review; it pops up straight away even before controllers are paired so the Apple reviewers will likely notice, and the quality of permission strings is often a reason for failed app reviews.

It would be better to delay requesting the permission until the microphone is actually used (I assume delaying photon voice until joining a room or something similar) but hopefully this is a quick fix that will get the update through review for now.

[tangobravo]

Ah so the blank camera permission fails some test in the MacOS build, as it looks like "Webcam Texture" is in use there for something. Not sure how easy it is to make this value vary per-platform.

[mikeage]

Note that we lost the Library/ caches for some of the Android platforms (and, I suppose, ios!) so the build is taking noticeably longer. I've rerun a build on main which should populate them, but it can take a few hours

Edit: caches are available; subsequent builds should be fast again