project upgraded to Android SDK 35, Java 17, and AGP 8.x

[PURUSHOTHAM-REDDY-N]

Summary

This PR upgrades the project to comply with the new Play Store requirement (targetSdk 35+ as of August 31, 2025) and modernizes the build toolchain. Both sample and payment modules are updated accordingly.

Key Changes

• Upgraded compileSdk and targetSdk to 35.
• Updated Java version from 11 to 17.
• Migrated to Android Gradle Plugin 8.x and Gradle 8.4.
• Added required namespace declarations for all modules.
• Updated dependency versions (Material, Robolectric, etc.).
• Synced project structure and runtime settings to support the new toolchain.
• Updated .idea configuration (auto-generated by Android Studio).

Purpose

• Ensure compatibility with upcoming Google Play requirements.
• Enable support for newer devices, APIs, and build features.
• Resolve old plugin and Gradle deprecation issues.
• I'm Planning to create ReactNative Plugin using the payments SDK for NPI

Testing

• Project builds successfully with AGP 8.x and Java 17.
• Sample app launches and compiles without errors
• Payment flow has NOT been tested because I do not have access to the required testing credentials.

[PURUSHOTHAM-REDDY-N]

Hi @chris-wilson-cs
I wanted to check in on this PR. It includes the required upgrades for targetSdk 35, AGP 8.x, and Java 17 to ensure the project remains compliant with upcoming Play Store requirements.

When you have a moment, could you please review the changes?
Payment flow testing is pending as I do not have the test credentials yet, but I’m happy to validate that part once the credentials are provided.

Thanks, and please let me know if you’d like any adjustments.