Improve API URL validation message

app/views/clusters/clusters/user/_form.html.haml

@@ -12,7 +12,7 @@
 
   = field.fields_for :platform_kubernetes, @user_cluster.platform_kubernetes do |platform_kubernetes_field|
     = platform_kubernetes_field.url_field :api_url, required: true,
-      title: s_('ClusterIntegration|API URL must use http or https protocol.'),
+      title: s_('ClusterIntegration|API URL should be a valid http/https url.'),
       label: s_('ClusterIntegration|API URL'), label_class: 'label-bold'
     = platform_kubernetes_field.text_area :ca_cert,
       placeholder: s_('ClusterIntegration|Certificate Authority bundle (PEM format)'),

locale/gitlab.pot

@@ -1710,7 +1710,7 @@ msgstr ""
 msgid "ClusterIntegration|API URL"
 msgstr ""
 
-msgid "ClusterIntegration|API URL must use http or https protocol."
+msgid "ClusterIntegration|API URL should be a valid http/https url."
 msgstr ""
 
 msgid "ClusterIntegration|Add Kubernetes cluster"