Fix render tracking event for issues_mrs_empty_state

What does this MR do and why?

Fix render tracking event for issues_mrs_empty_state experiment.

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.

Screenshots or screen recordings

!147661 (merged)

How to set up and validate locally

bin/rails c

Feature.enable(:issues_mrs_empty_state)

• Setup gdk to simulate SaaS - https://docs.gitlab.com/ee/development/ee_features.html#simulate-a-saas-instance and restart GDK
• Sign up. Create new group and blank project under that group.
• Visit project MRs list.
• Mare sure frontend events from the table below are generated.
• Visit project issues list.
• Mare sure frontend events from the table below are generated.

For the MRs empty state:

sequence	activity	category	action	label
	(Control/Candidate) User renders MR empty state page - question are we able to tell from where? ex. Nav, Learn GitLab, etc.	projects:merge_requests:index	render	project_mrs_empty_list

For the Issues empty state:

sequence	activity	category	action	label
	(Control/Candidate) User renders Issues empty state page - question are we able to tell from where? ex. Nav, Learn GitLab, etc.	projects:issues:index	render	project_issues_empty_list

Related to #436480 (closed)