Add customerSessionClientSecret to CustomerRepository.CustomerInfo.

[jaynewstrom-stripe]

Summary

This is pre work required to call the new detach endpoint.

This pipes customerSessionClientSecret through when using customerSessions, and null otherwise. We will use this later to determine which endpoint to use, and authenticate.

[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 │     2 MiB │     2 MiB │  0 B │   4.1 MiB │   4.1 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 │ 301.8 KiB │ 301.8 KiB │  0 B │ 455.5 KiB │ 455.5 KiB │  0 B 
   native │   6.2 MiB │   6.2 MiB │  0 B │  15.8 MiB │  15.8 MiB │  0 B 
    asset │   7.1 KiB │   7.1 KiB │  0 B │   6.9 KiB │   6.9 KiB │  0 B 
    other │  90.2 KiB │  90.2 KiB │ +3 B │ 170.3 KiB │ 170.3 KiB │  0 B 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
    total │   9.6 MiB │   9.6 MiB │ +3 B │  21.5 MiB │  21.5 MiB │  0 B 

 DEX     │ old   │ new   │ diff      
─────────┼───────┼───────┼───────────
   files │     1 │     1 │ 0         
 strings │ 19966 │ 19966 │ 0 (+0 -0) 
   types │  6188 │  6188 │ 0 (+0 -0) 
 classes │  4979 │  4979 │ 0 (+0 -0) 
 methods │ 29759 │ 29759 │ 0 (+0 -0) 
  fields │ 17526 │ 17526 │ 0 (+0 -0) 

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  164 │  164 │  0   
 entries │ 3622 │ 3622 │  0

APK

   compressed    │  uncompressed   │                        
──────────┬──────┼──────────┬──────┤                        
 size     │ diff │ size     │ diff │ path                   
──────────┼──────┼──────────┼──────┼────────────────────────
 25.3 KiB │ +2 B │ 62.8 KiB │  0 B │ ∆ META-INF/MANIFEST.MF 
  1.2 KiB │ +1 B │  1.2 KiB │  0 B │ ∆ META-INF/CERT.RSA    
──────────┼──────┼──────────┼──────┼────────────────────────
 26.5 KiB │ +3 B │ 64.1 KiB │  0 B │ (total)