Migrate widget view events to internal events

What does this MR do and why?

This is 1st part of migrating code review events to internal events.

Type of Events	MR Link
view merge request	!156609
click on full report merge request	TODO
expand merge request	TODO

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

• Apply below patch

diff --git a/app/assets/javascripts/vue_merge_request_widget/components/widget/app.vue b/app/assets/javascripts/vue_merge_request_widget/components/widget/app.vue
index e1d6b22b6f0fb..f01af75e3ec94 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/widget/app.vue
+++ b/app/assets/javascripts/vue_merge_request_widget/components/widget/app.vue
@@ -22,19 +22,19 @@ export default {
 
   computed: {
     testReportWidget() {
-      return this.mr.testResultsPath && 'MrTestReportWidget';
+      return 'MrTestReportWidget';
     },
 
     terraformPlansWidget() {
-      return this.mr.terraformReportsPath && 'MrTerraformWidget';
+      return 'MrTerraformWidget';
     },
 
     codeQualityWidget() {
-      return this.mr.codequalityReportsPath ? 'MrCodeQualityWidget' : undefined;
+      return 'MrCodeQualityWidget';
     },
 
     accessibilityWidget() {
-      return this.mr.accessibilityReportPath ? 'MrAccessibilityWidget' : undefined;
+      return 'MrAccessibilityWidget';
     },
 
     widgets() {

• Open any merge request, it should send track_event API call with test_summary, terraform, code_quality and accessibility events.

Related to #448283