Merge some monitoring dashboard Vue files

Summary

Refactor the following monitoring dashboard js files. These files were moved into CE from EE. Since there were already existing files with the same name, they were renamed based on the functionality they provide. However, since alerting is now part of GitLab Core, there is no reason to separate out the functionality into different files.

• app/assets/javascripts/monitoring/components/dashboard_with_alerts.vue
• app/assets/javascripts/monitoring/monitoring_bundle_with_alerts.js
• app/assets/javascripts/monitoring/components/panel_type_with_alerts.vue
• spec/frontend/monitoring/components/panel_type_with_alerts_spec.js

The above files can be merged into the following respective files:

• app/assets/javascripts/monitoring/components/dashboard.vue
• app/assets/javascripts/monitoring/monitoring_bundle.js
• app/assets/javascripts/monitoring/components/panel_type.vue
• spec/frontend/monitoring/components/panel_type_spec.js

Improvements

• There is no reason for these files to be separated anymore.
• Reduces the number of files in the app/assets/javascripts/monitoring folder.

Risks

The alert widget on the metrics dashboard might break. The existing frontend specs should catch it.

Involved components

• app/assets/javascripts/monitoring/components/dashboard_with_alerts.vue
• app/assets/javascripts/monitoring/monitoring_bundle_with_alerts.js
• app/assets/javascripts/monitoring/components/panel_type_with_alerts.vue
• spec/frontend/monitoring/components/panel_type_with_alerts_spec.js

These files were moved from EE into Core in !29789 (merged).

Optional: Intended side effects

Optional: Missing test coverage