[MOBILESDK-2681] [MOBILESDK-2682] Default Payment Method Label Feature Flag

[tianzhao-stripe]

Summary

Added feature flag for default payment method

Motivation

https://jira.corp.stripe.com/browse/MOBILESDK-2681
https://jira.corp.stripe.com/browse/MOBILESDK-2682

Testing

• Added tests
• Modified tests
• Manually verified

Screenshots

N.A.

Changelog

N.A.

[github-actions]

Diffuse output:

OLD: paymentsheet-example-release-master.apk (signature: V1, V2)
NEW: paymentsheet-example-release-pr.apk (signature: V1, V2)

          │          compressed           │        uncompressed         
          ├───────────┬───────────┬───────┼──────────┬──────────┬───────
 APK      │ old       │ new       │ diff  │ old      │ new      │ diff  
──────────┼───────────┼───────────┼───────┼──────────┼──────────┼───────
      dex │   3.9 MiB │   3.9 MiB │ -81 B │  8.6 MiB │  8.6 MiB │ +92 B 
     arsc │   2.3 MiB │   2.3 MiB │   0 B │  2.3 MiB │  2.3 MiB │   0 B 
 manifest │     5 KiB │     5 KiB │   0 B │ 24.9 KiB │ 24.9 KiB │   0 B 
      res │ 908.4 KiB │ 908.4 KiB │   0 B │  1.4 MiB │  1.4 MiB │   0 B 
   native │   2.6 MiB │   2.6 MiB │   0 B │    6 MiB │    6 MiB │   0 B 
    asset │   1.6 MiB │   1.6 MiB │   0 B │  1.6 MiB │  1.6 MiB │   0 B 
    other │   1.4 MiB │   1.4 MiB │  +6 B │  1.6 MiB │  1.6 MiB │   0 B 
──────────┼───────────┼───────────┼───────┼──────────┼──────────┼───────
    total │  12.6 MiB │  12.6 MiB │ -75 B │ 21.5 MiB │ 21.5 MiB │ +92 B 

 DEX     │ old   │ new   │ diff       
─────────┼───────┼───────┼────────────
   files │     1 │     1 │  0         
 strings │ 40547 │ 40548 │ +1 (+2 -1) 
   types │ 13985 │ 13985 │  0 (+0 -0) 
 classes │ 11660 │ 11660 │  0 (+0 -0) 
 methods │ 59552 │ 59552 │  0 (+0 -0) 
  fields │ 39749 │ 39750 │ +1 (+1 -0) 

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  243 │  243 │  0   
 entries │ 6208 │ 6208 │  0

APK

    compressed    │   uncompressed    │                                           
──────────┬───────┼───────────┬───────┤                                           
 size     │ diff  │ size      │ diff  │ path                                      
──────────┼───────┼───────────┼───────┼───────────────────────────────────────────
  3.9 MiB │ -81 B │   8.6 MiB │ +92 B │ ∆ classes.dex                             
 50.2 KiB │  +4 B │ 118.4 KiB │   0 B │ ∆ META-INF/MANIFEST.MF                    
 53.5 KiB │  +2 B │ 118.5 KiB │   0 B │ ∆ META-INF/CERT.SF                        
    271 B │  -1 B │     120 B │   0 B │ ∆ META-INF/version-control-info.textproto 
  1.2 KiB │  +1 B │   1.2 KiB │   0 B │ ∆ META-INF/CERT.RSA                       
──────────┼───────┼───────────┼───────┼───────────────────────────────────────────
    4 MiB │ -75 B │   8.8 MiB │ +92 B │ (total)

DEX

STRINGS:

   old   │ new   │ diff       
  ───────┼───────┼────────────
   40547 │ 40548 │ +1 (+2 -1) 
  
  + Enable Default Payment Methods
  + ~~R8{"backend":"dex","compilation-mode":"release","has-checksums":false,"min-api":21,"pg-map-id":"c8dcae0","r8-mode":"full","version":"8.7.14"}
  
  - ~~R8{"backend":"dex","compilation-mode":"release","has-checksums":false,"min-api":21,"pg-map-id":"92807e8","r8-mode":"full","version":"8.7.14"}
  

FIELDS:

   old   │ new   │ diff       
  ───────┼───────┼────────────
   39749 │ 39750 │ +1 (+1 -0) 
  
  + i5.d c: t