chore: [SDK-4728] add no-location demo and switch to env var opt-out

[fadi-george]

Description

One Line Summary

Adds the demo-no-location example app and switches the disable-location opt-out to a single ONESIGNAL_DISABLE_LOCATION environment variable.

Details

Motivation

Stacked on top of #1953. That PR added the ability to exclude OneSignal's native location module. This PR:

1. Replaces the per-platform knobs introduced in feat: [SDK-4728] support disabling location module #1953 (Android OneSignal_disableLocation gradle property and iOS $OneSignalDisableLocation Podfile global) with a single ONESIGNAL_DISABLE_LOCATION environment variable, read at dependency-resolution time on both platforms. This keeps the opt-out consistent across iOS (CocoaPods) and Android (Gradle), and matches the approach used in the OneSignal Flutter SDK.
2. Adds a minimal runnable examples/demo-no-location app that proves push + in-app messaging work without linking the native location module, and cleans up cruft that was copied into it (the unused com.demo Android package and the orphaned vine_boom.wav asset with its dangling Xcode references).

Scope

• Core SDK: android/build.gradle and react-native-onesignal.podspec now read ONESIGNAL_DISABLE_LOCATION; default behavior (location included) is unchanged when the variable is unset.
• Demo only otherwise; no runtime SDK code paths change.

Testing

Manual testing

Validated with clean reinstalls in examples/demo-no-location:

• iOS (pod install with the env var, via the Podfile): Podfile.lock resolves react-native-onesignal to OneSignalXCFramework/OneSignal + OneSignalXCFramework/OneSignalInAppMessages only — no OneSignalLocation subspec.
• Android (./gradlew :app:dependencies with the env var): resolves com.onesignal:core + notifications + in-app-messages (+ transitive otel), with no com.onesignal:location and no aggregate com.onesignal:OneSignal.
• Control (Android without the env var): the aggregate com.onesignal:OneSignal pulls com.onesignal:location back in, confirming the variable is what excludes the module.

Affected code checklist

• Public API changes (build-time opt-out mechanism)

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Made with Cursor

[sherwinski]

1. https://github.com/OneSignal/react-native-onesignal/blob/fadi/sdk-4728-cleanup/examples/demo/ios/demo/vine_boom.wav is still on disk even though it's dereferenced in res/raw. We should remove it there too.
2. To avoid headaches in testing, we should normalize how we parse ONESIGNAL_DISABLE_LOCATION from env:
   a. Android: value.toString().toBoolean() is case-insensitive, so true/TRUE/True all work, but 1 does not.
   b. iOS: ENV['ONESIGNAL_DISABLE_LOCATION'] == 'true' requires case-sensitive exact match, so TRUE and 1 both fail.