[fuchsia] Remove soon to be deleted header file.

environment_services.h would be deleted soon. It is no longer used, so
removing the reference.

CP-120 #comment

Change-Id: I7b1e4e78e3558e01a21afd75eae4f6866edb2c9f
Reviewed-on: https://dart-review.googlesource.com/72083
Commit-Queue: Zach Anderson <zra@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
diff --git a/runtime/vm/os_fuchsia.cc b/runtime/vm/os_fuchsia.cc
index 17b21ad..a6b7a18 100644
--- a/runtime/vm/os_fuchsia.cc
+++ b/runtime/vm/os_fuchsia.cc
@@ -16,7 +16,6 @@
 
 #include <fuchsia/timezone/cpp/fidl.h>
 
-#include "lib/component/cpp/environment_services.h"
 #include "lib/component/cpp/startup_context.h"
 #include "lib/svc/cpp/services.h"