Removed option to schedule a GA3 import, #PG-3619

[AltamashShaikh]

Description:

Removed option to schedule a GA3 import
Fixes: #PG-3619

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

[araichyk]

Couldn't test personally, but changes look appropriate. LGTM 👍

[snake14]

Nice work! I confirmed that I can only create new GA4 imports, I can no longer re-import date ranges for existing UA imports, and I receive an error message when running the UA console command.