[fuchsia] Update the "shell" feature to "deprecated-shell".

The feature name was renamed in Fuchsia. There is no permanent
replacement for accessing "/hub" as of yet.

Bug: 977730
Change-Id: Ice51e0d5a5464e596129f5b9aad075040d2a9510
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1671860
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#671441}

fuchsia/engine/integration_tests_sandbox_policy

 {
   "features": [
       "isolated-persistent-storage",
-      "shell",
+      "deprecated-shell",
       "system-temp" ],
   "services": [
       "fuchsia.logger.LogSink",