Rename method to #each_eligible_shard

app/workers/concerns/each_shard_worker.rb

@@ -6,7 +6,7 @@ module EachShardWorker
     Gitlab::HealthChecks::GitalyCheck
   ].freeze
 
-  def each_shard
+  def each_eligible_shard
     Gitlab::ShardHealthCache.update(eligible_shard_names)
 
     eligible_shard_names.each do |shard_name|

app/workers/repository_check/dispatch_worker.rb

@@ -7,7 +7,7 @@ module RepositoryCheck
     def perform
       return unless Gitlab::CurrentSettings.repository_checks_enabled
 
-      each_shard do |shard_name|
+      each_eligible_shard do |shard_name|
         RepositoryCheck::BatchWorker.perform_async(shard_name)
       end
     end