feat: add coroutine Maps SDK initialization

[arpitagarwal1301]

Fixes #228

• Add Context.awaitMapsSdkInitialized() for coroutine-based Maps SDK initialization.
• Return the renderer actually loaded and preserve the optional renderer preference.
• Throw GooglePlayServicesNotAvailableException with the SDK status code on initialization failure.
• Add focused success and failure coverage.

Verification

• ./gradlew :maps-ktx:testDebugUnitTest --tests 'com.google.maps.android.ktx.MapsInitializerTest'
• ./gradlew :maps-ktx:testDebugUnitTest :maps-ktx:lintDebug
• ./gradlew build jacocoTestReport
• git diff --check

Limitations

• Live Play Services initialization was not exercised on a device or emulator; the callback and status contracts are covered with static mocks and verified against Maps SDK 20.0.0 bytecode.