Fix new issue page breakpoints

app/assets/stylesheets/bootstrap_migration.scss

@@ -43,7 +43,9 @@ a {
 .form-group.row .col-form-label {
   // Bootstrap 4 aligns labels to the left
   // for horizontal forms
-  text-align: right;
+  @include media-breakpoint-up(md) {
+    text-align: right;
+  }
 }
 
 table {

app/views/shared/issuable/form/_metadata.html.haml

@@ -8,28 +8,28 @@
 
 %hr
 .row
-  %div{ class: (has_due_date ? "col-lg-6" : "col-sm-12") }
+  %div{ class: (has_due_date ? "col-lg-6" : "col-12") }
     .form-group.row.issue-assignee
       - if issuable.is_a?(Issue)
         = render "shared/issuable/form/metadata_issue_assignee", issuable: issuable, form: form, has_due_date: has_due_date
       - else
         = render "shared/issuable/form/metadata_merge_request_assignee", issuable: issuable, form: form, has_due_date: has_due_date
     .form-group.row.issue-milestone
-      = form.label :milestone_id, "Milestone", class: "col-form-label #{has_due_date ? "col-lg-4" : "col-sm-2"}"
-      .col-sm-10{ class: ("col-lg-8" if has_due_date) }
+      = form.label :milestone_id, "Milestone", class: "col-form-label #{has_due_date ? "col-md-2 col-lg-4" : "col-2"}"
+      .col-10{ class: ("col-md-8" if has_due_date) }
         .issuable-form-select-holder
           = render "shared/issuable/milestone_dropdown", selected: issuable.milestone, name: "#{issuable.class.model_name.param_key}[milestone_id]", show_any: false, show_upcoming: false, show_started: false, extra_class: "js-issuable-form-dropdown js-dropdown-keep-input", dropdown_title: "Select milestone"
     .form-group.row
       - has_labels = @labels && @labels.any?
-      = form.label :label_ids, "Labels", class: "col-form-label #{has_due_date ? "col-lg-4" : "col-sm-2"}"
+      = form.label :label_ids, "Labels", class: "col-form-label #{has_due_date ? "col-md-2 col-lg-4" : "col-2"}"
       = form.hidden_field :label_ids, multiple: true, value: ''
-      .col-sm-10{ class: "#{"col-lg-8" if has_due_date} #{'issuable-form-padding-top' if !has_labels}" }
+      .col-10{ class: "#{"col-md-8" if has_due_date} #{'issuable-form-padding-top' if !has_labels}" }
         .issuable-form-select-holder
           = render "shared/issuable/label_dropdown", classes: ["js-issuable-form-dropdown"], selected: issuable.labels, data_options: { field_name: "#{issuable.class.model_name.param_key}[label_ids][]", show_any: false}, dropdown_title: "Select label"
   - if has_due_date
     .col-lg-6
       .form-group.row
-        = form.label :due_date, "Due date", class: "col-form-label col-sm-2"
-        .col-sm-10
+        = form.label :due_date, "Due date", class: "col-form-label col-md-2 col-lg-4"
+        .col-8
           .issuable-form-select-holder
             = form.text_field :due_date, id: "issuable-due-date", class: "datepicker form-control", placeholder: "Select due date"

app/views/shared/issuable/form/_metadata_issue_assignee.html.haml

-= form.label :assignee_ids, "Assignee", class: "col-form-label #{"col-lg-4" if has_due_date}"
-.col-sm-10{ class: ("col-lg-8" if has_due_date) }
+= form.label :assignee_ids, "Assignee", class: "col-form-label #{"col-md-2 col-lg-4" if has_due_date}"
+.col-sm-10{ class: ("col-md-8" if has_due_date) }
   .issuable-form-select-holder.selectbox
     - issuable.assignees.each do |assignee|
       = hidden_field_tag "#{issuable.to_ability_name}[assignee_ids][]", assignee.id, id: nil, data: { meta: assignee.name, avatar_url: assignee.avatar_url, name: assignee.name, username: assignee.username }