Set up Connect SDK Module

[simond-stripe]

Summary

Set up the scaffolding for the Connect SDK. This PR sets up two new modules:

1. stripe-connect: the module for the Connect SDK. This is what clients will call to use the Connect Embedded Components.
2. stripe-connect-example: the module containing the demo app showing off how to use the Connect SDK.

Motivation

Prepare for adding APIs implementation to the new Connect SDK.

Testing

• Added tests
• Modified tests
• Manually verified

[github-actions]

Risky Change

This is considered a risky change because it adjusts the sample app build.gradle, please review carefully.
We've seen issues in the past which resulted in failed builds for merchants. Please make sure the build.gradle change is intended.

By adding the label accept-risky-change to this PR, I acknowledge that I'm changing an example app and have verified that the SDK remains in a shippable state.

[simond-stripe]

Accepted risky change due to test run failure: https://github.com/stripe/stripe-android/actions/runs/10743658522/job/29798864778?pr=9203

I'm changing the build.gradle file, but it's to exempt the new sample app from the .api checks which is valid. No changes which affect the other SDKs

[github-actions]

Diffuse output:

OLD: identity-example-release-base.apk (signature: V1, V2)
NEW: identity-example-release-pr.apk (signature: V1, V2)

          │          compressed          │         uncompressed         
          ├───────────┬───────────┬──────┼───────────┬───────────┬──────
 APK      │ old       │ new       │ diff │ old       │ new       │ diff 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
      dex │   1.9 MiB │   1.9 MiB │  0 B │     4 MiB │     4 MiB │  0 B 
     arsc │     1 MiB │     1 MiB │  0 B │     1 MiB │     1 MiB │  0 B 
 manifest │   2.3 KiB │   2.3 KiB │  0 B │     8 KiB │     8 KiB │  0 B 
      res │ 301.5 KiB │ 301.5 KiB │  0 B │   455 KiB │   455 KiB │  0 B 
   native │   6.2 MiB │   6.2 MiB │  0 B │  15.8 MiB │  15.8 MiB │  0 B 
    asset │   6.8 KiB │   6.8 KiB │  0 B │   6.5 KiB │   6.5 KiB │  0 B 
    other │  85.5 KiB │  85.5 KiB │ +4 B │ 158.7 KiB │ 158.7 KiB │  0 B 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
    total │   9.5 MiB │   9.5 MiB │ +4 B │  21.4 MiB │  21.4 MiB │  0 B 

 DEX     │ old   │ new   │ diff      
─────────┼───────┼───────┼───────────
   files │     1 │     1 │ 0         
 strings │ 20227 │ 20227 │ 0 (+0 -0) 
   types │  6086 │  6086 │ 0 (+0 -0) 
 classes │  4894 │  4894 │ 0 (+0 -0) 
 methods │ 29483 │ 29483 │ 0 (+0 -0) 
  fields │ 17371 │ 17371 │ 0 (+0 -0) 

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  164 │  164 │  0   
 entries │ 3608 │ 3608 │  0

APK

   compressed    │   uncompressed   │                                           
──────────┬──────┼───────────┬──────┤                                           
 size     │ diff │ size      │ diff │ path                                      
──────────┼──────┼───────────┼──────┼───────────────────────────────────────────
 28.3 KiB │ +9 B │  62.6 KiB │  0 B │ ∆ META-INF/CERT.SF                        
 25.1 KiB │ -5 B │  62.5 KiB │  0 B │ ∆ META-INF/MANIFEST.MF                    
    270 B │ -2 B │     120 B │  0 B │ ∆ META-INF/version-control-info.textproto 
  1.2 KiB │ +2 B │   1.2 KiB │  0 B │ ∆ META-INF/CERT.RSA                       
──────────┼──────┼───────────┼──────┼───────────────────────────────────────────
 54.9 KiB │ +4 B │ 126.4 KiB │  0 B │ (total)

[amk-stripe]

Can you make the javadoc and the message here specific to the connect SDK private beta? A good example of this is the ExperimentalCustomerSessionApi annotation. (You could also get rid of the javadoc entirely if you want, I think)

[amk-stripe]

Generally, we annotate these with @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP) before they're released. That will ensure that these are not actually included in our public API yet. Then, whenever you're ready to ship private beta, you can send out a PR which just removes the annotation and adds a changelog entry about the new feature/product being available. I'd recommend that approach here

[simond-stripe]

Great idea! I like this approach a lot

[amk-stripe]

agreed!

[amk-stripe]

I would expect this to be ~empty until you launch private beta. I left a comment below which I think will help with that.

There's some stuff that shows up here which is unavoidable and just generated code, e.g. the ComposableSingleton, but hopefully most stuff won't be visible here yet!

[simond-stripe]

There's still a decent amount of generated stuff in there unfortunately (like the ComposableSingleton), but it's empty in terms of things consumers can actually call in practice 🙂

[simond-stripe]

@amk-stripe thanks for the feedback, ready for re-review!