[scenic] Move scenic_tools to shell binaries

Remove them from deprecated_system_image, make them deployed as shell
binaries instead.

TEST=Run `fx serve`. Run `set_root_view`. Modify `set_root_view` in a
user-visible way and build. Confirm that `set_root_view` now runs with
the updated code, without needing to repave.

Change-Id: I4c86efbfcf3bbdbd77d9579a4f02344c5c8192ba
diff --git a/bin/ui/BUILD.gn b/bin/ui/BUILD.gn
index 8eaba65..066b776 100644
--- a/bin/ui/BUILD.gn
+++ b/bin/ui/BUILD.gn
@@ -196,7 +196,6 @@
 }
 
 package("scenic_tools") {
-  deprecated_system_image = true
 
   deps = [
     "gltf_export",
@@ -212,27 +211,35 @@
   binaries = [
     {
       name = "gltf_export"
+      shell = true
     },
     {
       name = "input"
+      shell = true
     },
     {
       name = "set_root_view"
+      shell = true
     },
     {
       name = "set_renderer_params"
+      shell = true
     },
     {
       name = "present_view"
+      shell = true
     },
     {
       name = "print_input"
+      shell = true
     },
     {
       name = "screencap"
+      shell = true
     },
     {
       name = "snapshot"
+      shell = true
     },
   ]
 }