Image Marker: Improve player dialogue player

[fwild]

The visuals are on figma:

This involves modifying ImageMarkerController.cs to:

• [ ] add temporary const string with "Augmentations of this step are superimposed on a real-world location using Computer Vision. Point the camera at what this photo shows." - this text can later be replaced with an editable text as depicted in the design
• [ ] create new dialogue type in the UI toolkit to display the string as depicted in the design (this will require a different visualisation on world space UI)
• [ ] add a button to bring up or preview of the image target (functionality already exists: icon shows up beside the image marker augmentation of the step)
• [ ] show this text and image target preview/button if the image target has not yet been detected ever
• [ ] minimise the menu if on mobiles, but not on iPad / worldspace UI and bring up the dialogue (this would have to be in the InitAsync method, just before the return statement. I would move the code from activityView_v2.cs in OnArrowButtonPressed to public methods minimize and maximize and invoke the minize then from InitAsync
• [ ] if marker is not visible anymore, there should be a locate glyph coming up pointing in the direction where it was last seen

[fwild]

Maybe we can put some cool vfx here as well: snapping the image target into place, when it is detected, and then exploding/magicking/etc. - like a better version of https://vimeo.com/channels/pal/122481481