Fix several viewport issues (#1045)

* Fix some FOV calculation viewport issues:
-Avoid calculating FOV if we've got an invalid viewport
-Don't override game mode FOV, let the active camera components manage it instead

* Fix viewport font positioning

This updates code in a few places to respect an API change/fix made to AtomFont - also switched the default value of m_virtual800x600ScreenSize to false as it's really behavior you want to opt into

* Don't activate CameraComponentController when in the Editor / not in game mode

Code/Framework/AzFramework/AzFramework/Font/FontInterface.h

@@ -54,7 +54,7 @@ namespace AzFramework
         AZ::Matrix3x4 m_transform = AZ::Matrix3x4::Identity(); //!< Transform to apply to text quads
         bool m_monospace = false; //!< disable character proportional spacing
         bool m_depthTest = false; //!< Test character against the depth buffer
-        bool m_virtual800x600ScreenSize = true; //!< Text placement and size are scaled relative to a virtual 800x600 resolution
+        bool m_virtual800x600ScreenSize = false; //!< Text placement and size are scaled relative to a virtual 800x600 resolution
         bool m_scaleWithWindow = false; //!< Font gets bigger as the window gets bigger
         bool m_multiline = true; //!< text respects ascii newline characters
     };