Disable trigger button

When making a request disable
the trigger button until redirected.

app/assets/javascripts/jobs/components/manual_variables_form.vue

@@ -43,6 +43,7 @@ export default {
       variables: [],
       key: '',
       secretValue: '',
+      triggerBtnDisabled: false,
     };
   },
   computed: {
@@ -98,6 +99,11 @@ export default {
         1,
       );
     },
+    trigger() {
+      this.triggerBtnDisabled = true;
+
+      this.triggerManualJob(this.variables);
+    },
   },
 };
 </script>
@@ -182,7 +188,9 @@ export default {
         variant="info"
         category="primary"
         :aria-label="__('Trigger manual job')"
-        @click="triggerManualJob(variables)"
+        :disabled="triggerBtnDisabled"
+        data-testid="trigger-manual-job-btn"
+        @click="trigger"
       >
         {{ action.button_title }}
       </gl-button>

spec/frontend/jobs/components/manual_variables_form_spec.js

@@ -23,6 +23,8 @@ describe('Manual Variables Form', () => {
     });
   };
 
+  const findTriggerBtn = () => wrapper.find('[data-testid="trigger-manual-job-btn"]');
+
   beforeEach(() => {
     factory(requiredProps);
   });
@@ -53,6 +55,10 @@ describe('Manual Variables Form', () => {
     expect(wrapper.find('a').attributes('href')).toBe(requiredProps.variablesSettingsUrl);
   });
 
+  it('trigger button is not disabled on mount', () => {
+    expect(findTriggerBtn().props('disabled')).toBe(false);
+  });
+
   describe('when adding a new variable', () => {
     it('creates a new variable when user types a new key and resets the form', (done) => {
       wrapper.vm