Fix crash when no bank is selected in AddPaymentMethodActivity

[brnunes-stripe]

Summary

Fix crash when no bank is selected on FPX and Netbanking bank selector view.

Motivation

RUN_MOBILESDK-732

Testing

• Added tests
• Modified tests
• Manually verified

[github-actions]

Diffuse output:

OLD: paymentsheet-example-release-master.apk (signature: none)
NEW: paymentsheet-example-release-pr.apk (signature: none)

          │          compressed           │          uncompressed          
          ├───────────┬───────────┬───────┼───────────┬───────────┬────────
 APK      │ old       │ new       │ diff  │ old       │ new       │ diff   
──────────┼───────────┼───────────┼───────┼───────────┼───────────┼────────
      dex │  12.1 MiB │  12.1 MiB │ -68 B │  41.1 MiB │  41.1 MiB │ +436 B 
     arsc │   1.6 MiB │   1.6 MiB │   0 B │   1.6 MiB │   1.6 MiB │    0 B 
 manifest │   2.7 KiB │   2.7 KiB │   0 B │  11.1 KiB │  11.1 KiB │    0 B 
      res │ 697.8 KiB │ 697.8 KiB │   0 B │   1.1 MiB │   1.1 MiB │    0 B 
    asset │  77.2 KiB │  77.2 KiB │   0 B │ 108.7 KiB │ 108.7 KiB │    0 B 
    other │  78.7 KiB │  78.7 KiB │   0 B │ 154.6 KiB │ 154.6 KiB │    0 B 
──────────┼───────────┼───────────┼───────┼───────────┼───────────┼────────
    total │  14.5 MiB │  14.5 MiB │ -68 B │    44 MiB │    44 MiB │ +436 B 

         │          raw           │            unique            
         ├────────┬────────┬──────┼────────┬────────┬────────────
 DEX     │ old    │ new    │ diff │ old    │ new    │ diff       
─────────┼────────┼────────┼──────┼────────┼────────┼────────────
   files │      3 │      3 │    0 │        │        │            
 strings │ 192293 │ 192294 │   +1 │ 173982 │ 173983 │ +1 (+2 -1) 
   types │  33448 │  33448 │    0 │  31647 │  31647 │  0 (+0 -0) 
 classes │  29237 │  29237 │    0 │  29237 │  29237 │  0 (+0 -0) 
 methods │ 168358 │ 168358 │    0 │ 163734 │ 163734 │  0 (+0 -0) 
  fields │ 123223 │ 123223 │    0 │ 122755 │ 122755 │  0 (+0 -0) 

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  298 │  298 │  0   
 entries │ 5394 │ 5394 │  0

APK

   compressed    │   uncompressed   │                
─────────┬───────┼─────────┬────────┤                
 size    │ diff  │ size    │ diff   │ path           
─────────┼───────┼─────────┼────────┼────────────────
 3.4 MiB │ -68 B │ 9.7 MiB │ +436 B │ ∆ classes2.dex 
─────────┼───────┼─────────┼────────┼────────────────
 3.4 MiB │ -68 B │ 9.7 MiB │ +436 B │ (total)

DEX

STRINGS:

   old    │ new    │ diff       
  ────────┼────────┼────────────
   173982 │ 173983 │ +1 (+2 -1) 
  + SMAP
  AddPaymentMethodFpxView.kt
  Kotlin
  *S Kotlin
  *F
  + 1 AddPaymentMethodFpxView.kt
  com/stripe/android/view/AddPaymentMethodFpxView
  + 2 fake.kt
  kotlin/jvm/internal/FakeKt
  + 3 _Collections.kt
  kotlin/collections/CollectionsKt___CollectionsKt
  *L
  1#1,104:1
  1#2:105
  817#3:106
  845#3,2:107
  1849#3,2:109
  *S KotlinDebug
  *F
  + 1 AddPaymentMethodFpxView.kt
  com/stripe/android/view/AddPaymentMethodFpxView
  *L
  85#1:106
  85#1:107,2
  88#1:109,2
  *E
  
  + SMAP
  AddPaymentMethodNetbankingView.kt
  Kotlin
  *S Kotlin
  *F
  + 1 AddPaymentMethodNetbankingView.kt
  com/stripe/android/view/AddPaymentMethodNetbankingView
  + 2 fake.kt
  kotlin/jvm/internal/FakeKt
  *L
  1#1,67:1
  1#2:68
  *E
  
  
  - SMAP
  AddPaymentMethodFpxView.kt
  Kotlin
  *S Kotlin
  *F
  + 1 AddPaymentMethodFpxView.kt
  com/stripe/android/view/AddPaymentMethodFpxView
  + 2 _Collections.kt
  kotlin/collections/CollectionsKt___CollectionsKt
  *L
  1#1,102:1
  817#2:103
  845#2,2:104
  1849#2,2:106
  *S KotlinDebug
  *F
  + 1 AddPaymentMethodFpxView.kt
  com/stripe/android/view/AddPaymentMethodFpxView
  *L
  83#1:103
  83#1:104,2
  86#1:106,2
  *E