don't bother caching a constant for feature flags

refs CNVS-30659

Change-Id: If90aedf26994f0012fa1efebf875451779c2cc97
Reviewed-on: https://gerrit.instructure.com/86712
Tested-by: Jenkins
Reviewed-by: Simon Williams <simon@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>

lib/feature_flags.rb

@@ -77,14 +77,12 @@ module FeatureFlags
   # each account that needs to be searched for a feature flag, in priority order,
   # starting with site admin
   def feature_flag_account_ids
+    return [Account.site_admin.global_id] if is_a?(User)
+
     RequestCache.cache('feature_flag_account_ids', self) do
       Rails.cache.fetch(['feature_flag_account_ids', self].cache_key) do
-        if is_a?(User)
-          chain = [Account.site_admin]
-        else
-          chain = account_chain(include_site_admin: true)
-          chain.shift if is_a?(Account)
-        end
+        chain = account_chain(include_site_admin: true)
+        chain.shift if is_a?(Account)
         chain.reverse.map(&:global_id)
       end
     end