Hides the GA4 Tag when trying to create a new tag, #PG-3996

[AltamashShaikh]

Description:

Hides the GA4 Tag when trying to create a new tag,
Fixes: #PG-3996

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

[snake14]

Good solution which allows existing tags to continue working 👍

I left one optional comment. Aside from that, the only thing that we might want to change is the GA4 Event tag description which references the GA4 tag:

[snake14]

Thank you for making the suggested changes. Everything looks good in code and functional testing 👍