Move USBankAccountForm into BankFormElement

[tillh-stripe]

Summary

Motivation

Testing

• Added tests
• Modified tests
• Manually verified

Screenshots

Before	After
before screenshot	after screenshot

Changelog

[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 │ +268 B │     4 MiB │     4 MiB │ +196 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 │   6.6 KiB │   6.6 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 │ +264 B │  21.4 MiB │  21.4 MiB │ +196 B 

 DEX     │ old   │ new   │ diff       
─────────┼───────┼───────┼────────────
   files │     1 │     1 │  0         
 strings │ 20252 │ 20257 │ +5 (+6 -1) 
   types │  6082 │  6082 │  0 (+0 -0) 
 classes │  4886 │  4886 │  0 (+0 -0) 
 methods │ 29463 │ 29463 │  0 (+0 -0) 
  fields │ 17389 │ 17389 │  0 (+0 -0) 

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

APK

    compressed     │   uncompressed    │                                           
──────────┬────────┼──────────┬────────┤                                           
 size     │ diff   │ size     │ diff   │ path                                      
──────────┼────────┼──────────┼────────┼───────────────────────────────────────────
  1.9 MiB │ +268 B │    4 MiB │ +196 B │ ∆ classes.dex                             
 28.3 KiB │   -7 B │ 62.6 KiB │    0 B │ ∆ META-INF/CERT.SF                        
 25.1 KiB │   +3 B │ 62.5 KiB │    0 B │ ∆ META-INF/MANIFEST.MF                    
    272 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                       
──────────┼────────┼──────────┼────────┼───────────────────────────────────────────
    2 MiB │ +264 B │  4.1 MiB │ +196 B │ (total)

DEX

STRINGS:

   old   │ new   │ diff       
  ───────┼───────┼────────────
   20252 │ 20257 │ +5 (+6 -1) 
  
  + bank_name
  + last4
  + link[payment_method_id]
  + us_bank_account[link_account_session]
  + uses_microdeposits
  + ~~R8{"backend":"dex","compilation-mode":"release","has-checksums":false,"min-api":21,"pg-map-id":"f64b23a","r8-mode":"full","version":"8.5.35"}
  
  - ~~R8{"backend":"dex","compilation-mode":"release","has-checksums":false,"min-api":21,"pg-map-id":"dc6e6d8","r8-mode":"full","version":"8.5.35"}