iOS replay initialized with native capture

[vaind]

Description

During testing it has happened to me that a native replay capture initialized. on iOS, it means we actually get the image but without any masking. We must ensure neither platform starts unless the flutter screenshot handler is used.

What happens is that when app is put to background, than after a while when a user launches it again, it starts a new replay that is done by the native layer instead of the Flutter screenshot recorder.

Sample replays:

• before app sleep https://sentry-sdks.sentry.io/replays/530bad2b0b9d4ffa961ad41c21218840/?project=5428562&query=&referrer=%2Freplays%2F&statsPeriod=7d&yAxis=count%28%29
• after resuming: https://sentry-sdks.sentry.io/replays/a0508f9b5fe64c328d38db4af95b5314/?project=5428562&query=&referrer=%2Freplays%2F&statsPeriod=7d&yAxis=count%28%29