chore: Update swiftlint to match stripe-ios

[yuki-stripe]

Summary

.

Testing

• I tested this manually
• I added automated tests

[I] yuki@st-yuki5 ~/s/stripe-react-native (yuki/match-swiftlint)> diff .swiftlint.yml ~/stripe/stripe-ios/.swiftlint.yml
3,5d2
< # Keep in sync with stripe-ios/.swiftlint.yml
< # (excluded paths and custom_rules may differ)
< #
15c12
<   - cyclomatic_complexity # This finds some hairy methods
---
>   - cyclomatic_complexity       # This finds some hairy methods
18c15
<   - function_body_length # Interesting overlap between these violations and cyclomatic_complexity
---
>   - function_body_length        # Interesting overlap between these violations and cyclomatic_complexity
35c32
<   - for_where
---
>   - for_where
73,74c70,75
<   - ios/Pods
<   - ios/build*
---
>   - Package.swift
>   - Pods
>   - Tests/installation_tests
>   - vendor
>   - build*
>   - .build
83c84
<   warning: 4 # It would be nice to lower this number
---
>   warning: 4                # It would be nice to lower this number
104c105
<   max_length: 30 # Maybe remove after initial cleanup.
---
>   max_length: 30          # Maybe remove after initial cleanup.
106a108,122
>   enum_safe_decodable:
>     name: "Use SafeEnumDecodable for enums"
>     message: "Enums in API Bindings should conform to SafeEnumDecodable or SafeEnumCodable instead of Decodable or Codable to handle unknown values gracefully."
>     regex: 'enum\s+(?!CodingKeys)\w+\s*(<[^>]*>)?\s*:\s*[^{]*(?<!SafeEnum)(Decodable|Codable)\b(?!Key)'
>     severity: error
>     included:
>       - "StripePaymentSheet/StripePaymentSheet/Source/Internal/API Bindings/"
>   no_shared_api_client_mutation_in_tests:
>     name: "Don't use STPAPIClient.shared in tests"
>     message: "Avoid setting STPAPIClient.shared.publishableKey in tests. Create a dedicated STPAPIClient instance instead to prevent test pollution. Note also that it's valid for merchants to pass their own instance of STPAPIClient and *not* use STPAPIClient.shared."
>     regex: 'STPAPIClient\.shared\.publishableKey\s*='
>     severity: warning
>     included:
>       - ".*Tests\\.swift$"
>       - ".*Tests/"

Documentation

Select one:

• I have added relevant documentation for my changes.
• This PR does not result in any developer-facing changes.