Fix thinclient address in dev builds and move thinclient (#586)

* Fix thinclient address in dev builds and move thinclient

Update USBFrameProvider.java

Create index.html

Update index.html

Null check stream to prevent spam

* Update main.yml

Co-authored-by: Chris Gerth <gerth2@users.noreply.github.com>

photon-core/src/main/java/org/photonvision/vision/videoStream/SocketVideoStreamManager.java

@@ -72,7 +72,9 @@ public class SocketVideoStreamManager {
         if (port != null && port != NO_STREAM_PORT) {
             var stream = streams.get(port);
             userSubscriptions.put(user, NO_STREAM_PORT);
-            stream.removeUser();
+            if (stream != null) {
+                stream.removeUser();
+            }
         } else {
             logger.error(
                     "User attempted to unsubscribe, but had not yet previously subscribed successfully.");