feat: update raygun4android dependency to 5.2.1 (#215)

[velocitysystems]

Update raygun4android dependency to 5.2.1

Resolves #215.

Description 📝

• Purpose: Update the raygun4android dependency from 4.2.1 to the latest version (5.2.1) to pick up the Kotlin rewrite, bug fixes, and improvements in the 5.x line.
• Approach: Bumped the dependency version in build.gradle, updated the minimum SDK version from 19 to 23 (required by raygun4android 5.x), and migrated the RaygunUserInfo constructor call to the new RaygunUserInfo.create() factory method (the constructor is now private in 5.x).

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Updates

👉 Updated com.raygun:raygun4android from 4.2.1 to 5.2.1 in sdk/android/build.gradle
👉 Bumped DEFAULT_MIN_SDK_VERSION from 19 to 23 (raygun4android 5.x requires Android 6+)
👉 Changed new RaygunUserInfo(...) to RaygunUserInfo.create(...) in RaygunNativeBridgeModule.java

Screenshots 📷

N/A

Test plan 🧪

• Verify the Android module builds successfully (./gradlew :raygun4reactnative:compileDebugJavaWithJavac)
• Run the demo app on an Android device/emulator and confirm crash reporting initialises without errors
• Trigger a test crash and verify it appears in the Raygun dashboard
• Set a user and verify user info is attached to crash reports
• Record a breadcrumb and verify it appears on crash reports
• Confirm RUM session events (resume/pause/end) still fire correctly

Author to check 👓

• Project and all contained modules builds successfully
• Self-/dev-tested
• Unit/UI/Automation/Integration tests provided where applicable
• Code is written to standards
• Appropriate documentation written (code comments, internal docs)

Reviewer to check ✔️

• Project and all contained modules builds successfully
• Change has been dev-/reviewer-tested, where possible
• Unit/UI/Automation/Integration tests provided where applicable
• Code is written to standards
• Appropriate documentation written (code comments, internal docs)

[velocitysystems]

Needs #223 to be merged first and then rebase required.

[TheRealAgentK]

The change looks fine.

There are demo build failures, but I would expect these to clean up when this PR is merged because master has sdk 36 now.