fix: FLAVOR_APP_NAME is not updating for 'Release-Production' in iOS

[Yijing Huang]

Description
I created a new flutter coro project called 'demo', but in the FLAVOR_APP_NAME, it always showtestApp not the name I set before like Demo

Steps To Reproduce

1. Create a new flutter core project by CLI
2. Open Runner.xcodeproj under iOS folder
3. search FLAVOR_APP_NAME under TARGETS Runner

Expected Behavior
Show corresponding app name not a fixed text.

[Alejandro Santiago]

Hi @hyj1204 👋 ! Thanks for opening an issue!

I was able to reproduce this issue using Very Good CLI 0.19.1 .