Migrate top-centered toasts to bottom-left

Top-centered toasts go against Pajamas specifications and have been
moved back to the bottom-left corner.

Changelog: changed
EE: true

ee/app/assets/javascripts/analytics/cycle_analytics/components/value_stream_form.vue

@@ -168,9 +168,7 @@ export default {
           const msg = this.isEditing
             ? this.$options.i18n.FORM_EDITED
             : this.$options.i18n.FORM_CREATED;
-          this.$toast.show(sprintf(msg, { name: this.name }), {
-            position: 'top-center',
-          });
+          this.$toast.show(sprintf(msg, { name: this.name }));
           this.name = '';
           this.nameError = [];
           this.stages = initializeStages(this.defaultStageConfig, this.selectedPreset);

ee/app/assets/javascripts/analytics/cycle_analytics/components/value_stream_select.vue

@@ -84,7 +84,7 @@ export default {
   methods: {
     ...mapActions(['setSelectedValueStream', 'deleteValueStream']),
     onSuccess(message) {
-      this.$toast.show(message, { position: 'top-center' });
+      this.$toast.show(message);
     },
     isSelected(id) {
       return Boolean(this.selectedValueStreamId && this.selectedValueStreamId === id);

ee/spec/frontend/analytics/cycle_analytics/components/value_stream_form_spec.js

@@ -315,9 +315,7 @@ describe('ValueStreamForm', () => {
           });
 
           it('displays a toast message', () => {
-            expect(mockToastShow).toHaveBeenCalledWith(`'${initialData.name}' Value Stream saved`, {
-              position: 'top-center',
-            });
+            expect(mockToastShow).toHaveBeenCalledWith(`'${initialData.name}' Value Stream saved`);
           });
 
           it('sends tracking information', () => {
@@ -411,9 +409,7 @@ describe('ValueStreamForm', () => {
       });
 
       it('displays a toast message', () => {
-        expect(mockToastShow).toHaveBeenCalledWith(`'${streamName}' Value Stream created`, {
-          position: 'top-center',
-        });
+        expect(mockToastShow).toHaveBeenCalledWith(`'${streamName}' Value Stream created`);
       });
 
       it('sends tracking information', () => {

ee/spec/frontend/analytics/cycle_analytics/components/value_stream_select_spec.js

@@ -202,9 +202,6 @@ describe('ValueStreamSelect', () => {
       it('displays a toast message', () => {
         expect(mockToastShow).toHaveBeenCalledWith(
           `'${selectedValueStream.name}' Value Stream deleted`,
-          {
-            position: 'top-center',
-          },
         );
       });