Change health status constants to use 0

When the health status is set as 'No status'
the input value will be 0.

app/assets/javascripts/issuable_bulk_update_actions.js

@@ -79,8 +79,6 @@ export default {
    */
 
   getFormDataAsObject() {
-    const healthStatusValue = this.form.find('input[name="update[health_status]"]').val();
-
     const formData = {
       update: {
         state_event: this.form.find('input[name="update[state_event]"]').val(),
@@ -88,7 +86,7 @@ export default {
         milestone_id: this.form.find('input[name="update[milestone_id]"]').val(),
         issuable_ids: this.form.find('input[name="update[issuable_ids]"]').val(),
         subscription_event: this.form.find('input[name="update[subscription_event]"]').val(),
-        health_status: healthStatusValue === 'null' ? '0' : healthStatusValue,
+        health_status: this.form.find('input[name="update[health_status]"]').val(),
         add_label_ids: [],
         remove_label_ids: [],
       },

ee/app/assets/javascripts/sidebar/constants.js

@@ -20,7 +20,7 @@ export const iterationSelectTextMap = {
 };
 
 export const healthStatusForRestApi = {
-  NO_STATUS: null,
+  NO_STATUS: '0',
   [healthStatus.ON_TRACK]: 'on_track',
   [healthStatus.NEEDS_ATTENTION]: 'needs_attention',
   [healthStatus.AT_RISK]: 'at_risk',

ee/spec/services/ee/issuable/bulk_update_service_spec.rb

@@ -64,6 +64,19 @@ RSpec.describe Issuable::BulkUpdateService do
             expect(issuable.health_status).to eq('on_track')
           end
         end
+
+        context "when params values are '0'" do
+          let(:params) { { issuable_ids: issuables.map(&:id), health_status: '0' } }
+
+          it 'succeeds and remove values' do
+            expect(subject[:success]).to be_truthy
+            expect(subject[:count]).to eq(issuables.count)
+            issuables.each do |issuable|
+              issuable.reload
+              expect(issuable.health_status).to be_nil
+            end
+          end
+        end
       end
 
       context 'when features are disabled' do