[modular][testing] disable flaky story_shell test.

The replacement version using the new test harness is in review.
Disabling this since it's flaky and in anticipation of that.

FLK-283 #done

Change-Id: Iafc223bf8d13b758d2a1acdd814b116933cad417
diff --git a/peridot/tests/modular_tests.json b/peridot/tests/modular_tests.json
index a64c348..d210eaa0 100644
--- a/peridot/tests/modular_tests.json
+++ b/peridot/tests/modular_tests.json
@@ -69,7 +69,8 @@
         "--session_shell=fuchsia-pkg://fuchsia.com/story_shell_test_session_shell#meta/story_shell_test_session_shell.cmx",
         "--story_shell=fuchsia-pkg://fuchsia.com/story_shell_test_story_shell#meta/story_shell_test_story_shell.cmx",
         "--sessionmgr_args=--use_memfs_for_ledger,--no_cloud_provider_for_ledger"
-      ]
+      ],
+      "disabled": true
     },
     {
       "name": "story_shell_factory",