fix: kotlin nullable-receiver compile errors in sdk-react-native android module

[ZayanKhan-12]

Description

@metamask/sdk-react-native fails to compile on Android with newer React Native versions (#1308):

MetaMaskReactNativeSdkModule.kt:140:29 Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type 'ReadableMap?'
MetaMaskReactNativeSdkModule.kt:141:35 …
MetaMaskReactNativeSdkModule.kt:182:45 … 'ReadableMap?'
MetaMaskReactNativeSdkModule.kt:183:49 … 'ReadableArray?'

Newer RN annotates ReadableArray.getMap(i) and Dynamic.asMap()/asArray() as @Nullable, so Kotlin rejects the unsafe calls. This handles the nulls explicitly:

• batchRequest: reqArray.getMap(i) ?: throw IllegalArgumentException("Request at index $i must be a map") — same failure mode as the existing missing-method check, and lines 140–141 then operate on a non-null receiver
• Dynamic.asAny(): safe calls (asMap()?.toHashMap(), asArray()?.toArrayList()) — the function already returns Any?

Both patterns compile identically against older RN where these getters are platform types, so no behavior change for existing consumers.

Fixes #1308

Testing

Mechanical null-safety change verified against the compiler errors reported in the issue (the reporter's repro is at Arthur-Kamau/react-native-sample). I don't have an Android toolchain in this environment to run compileDebugKotlin locally — flagging that honestly; the change only touches the four reported lines.

🤖 Generated with Claude Code

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Note

Low Risk
Tiny compile-time null-handling change in the Android bridge; intended behavior unchanged on older RN, with slightly clearer errors for malformed batch entries.

Overview
Fixes Android build failures on newer React Native versions where ReadableArray.getMap, Dynamic.asMap, and Dynamic.asArray are @Nullable, which broke Kotlin compilation in MetaMaskReactNativeSdkModule.

In batchRequest, a null entry from getMap(i) now throws IllegalArgumentException (aligned with existing validation for missing method). In Dynamic.asAny(), map/array branches use safe calls so nested params can resolve to null without crashing the compiler.

Changelog updated under Unreleased → Fixed.

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