Increase wait time for validating Docker image

app/models/execution_environment.rb

@@ -93,9 +93,9 @@ class ExecutionEnvironment < ApplicationRecord
     rescue Runner::Error => e
       # In case of an Runner::Error, we retry multiple times before giving up.
       # The time between each retry increases to allow the runner management to catch up.
-      if retries < 5 && !Rails.env.test?
+      if retries < 30 && !Rails.env.test?
         retries += 1
-        sleep retries
+        sleep 1.second.to_i
         retry
       elsif errors.exclude?(:docker_image)
         errors.add(:docker_image, "error: #{e}")