[Customer Center]: fix navigation when embedded in NavigationStack

[aboedo]

Fixes the navigation issues for Customer Center when presented through a NavigationStack.

Solves the issue by adding an extra optional parameter that you use when showing CustomerCenterView in a NavigationStack:

    CustomerCenterView(isInNavigationStack: true)

Before	After
https://github.com/user-attachments/assets/68154d11-8a82-43e0-95ec-482c0c40446d	https://github.com/user-attachments/assets/034b1b88-a0ef-4e90-9d4c-cec4cddaa72b

The Problem:

When presenting the Customer Center in a navigation stack, if we add another one, we kinda break navigation. I reproduced this in a very, very simple SwiftUI app:

What happens is that you go into customer center, it flashes but then automatically dismisses as soon as it loads, because the internal navigation stack and the external one kinda fight each other. If you try to tap again, it errors out.

The Solution

The solution is actually dead simple - if we're already in a NavigationStack, we don't create a new one.

What I don't love about this solution is that we do kind of give the consumer the responsibility of passing in this parameter correctly, but I tried my best to find ways around it to auto-detect and couldn't come up with something reliable.

And it doesn't feel that complicated of a thing to pass in.

Still to be done:

• API Tests
• Do we need to update the presentation modes? Do we want to reuse presentation modes? I kinda tried but it didn't fit all that well since it's meant for sheets, but maybe it can be fitted better.
• Do we need to update events / metrics for this?

[aboedo]

@vegaro hope this is helpful! Can you take it from here to the finish line if it is?

[aboedo]

cc @ajpallares @facumenzella

[hiddevdploeg]

Personally I'd prefer something like this:

NavigationLink("Customer Center") {
     CustomerCenterView()
}

ContentView()
.sheet(isPresented: $presentCustomerCenter) {
     CustomerCenterSheetView()
}

But I understand this would mean a everyone right now would have to refactor their current implementation so maybe CustomerCenterNavigationView() would make more sense?

Or we would create our own NavigationLink that looks something like this:

CustomerCenterNavigationLink {
     // Label goes here
}

Just my 2cts 😄

[facumenzella]

@hiddevdploeg I'll open a follow-up PR after this one addressing your comments. I like it

[tonidero]

Just a heads up that I'm adding the pr:RevenueCatUI label so the changelog gets generated correctly