Add PaymentOption.iconPainter for easier Compose integration

[tillh-stripe]

Summary

Adds a new public API for easier compose integration.

API Review: https://jira.corp.stripe.com/browse/MOBILE_APIREVIEW-70

[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 │   1.4 MiB │   1.4 MiB │  0 B │   1.4 MiB │   1.4 MiB │  0 B 
 manifest │   2.3 KiB │   2.3 KiB │  0 B │   8.1 KiB │   8.1 KiB │  0 B 
      res │ 363.2 KiB │ 363.2 KiB │  0 B │ 490.6 KiB │ 490.6 KiB │  0 B 
   native │   6.2 MiB │   6.2 MiB │  0 B │  15.8 MiB │  15.8 MiB │  0 B 
    asset │  67.8 KiB │  67.8 KiB │  0 B │  87.7 KiB │  87.7 KiB │  0 B 
    other │ 114.7 KiB │ 114.7 KiB │ +2 B │ 270.3 KiB │ 270.3 KiB │  0 B 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
    total │  10.2 MiB │  10.2 MiB │ +2 B │  22.2 MiB │  22.2 MiB │  0 B 

 DEX     │ old   │ new   │ diff      
─────────┼───────┼───────┼───────────
   files │     1 │     1 │ 0         
 strings │ 20963 │ 20963 │ 0 (+0 -0) 
   types │  6509 │  6509 │ 0 (+0 -0) 
 classes │  5298 │  5298 │ 0 (+0 -0) 
 methods │ 30646 │ 30646 │ 0 (+0 -0) 
  fields │ 17817 │ 17817 │ 0 (+0 -0) 

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  262 │  262 │  0   
 entries │ 5504 │ 5504 │  0

APK

   compressed   │  uncompressed  │                     
─────────┬──────┼─────────┬──────┤                     
 size    │ diff │ size    │ diff │ path                
─────────┼──────┼─────────┼──────┼─────────────────────
 1.2 KiB │ +2 B │ 1.2 KiB │  0 B │ ∆ META-INF/CERT.RSA 
─────────┼──────┼─────────┼──────┼─────────────────────
 1.2 KiB │ +2 B │ 1.2 KiB │  0 B │ (total)