Track load performance widget expansions via usage ping

What does this MR do?

For #10687 (closed)

This MR tracks the i_testing_load_performance_widget_total event when the load performance MR widget is expanded

Screenshots

the network request that tracks the event	the widget, for reference

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done