Release 5.2.3

[jennantilla]

What's Changed

✨ Improvements

• Removed duplicate "longer" MIGRATION_GUIDE.md (Removed duplicate "longer" MIGRATION_GUIDE.md #914)
• Set wrapper sdk type before calling initialize (Set wrapper sdk type before calling initialize #932)

🔧 Native Updates

Update Android SDK from 5.1.17 to 5.1.20 release notes

🐛 Bug Fixes

• IAM with dynamic trigger showing forever ([FIX] IAM with dynamic trigger showing forever OneSignal-Android-SDK#2137)
• Allow preventDefault to be fired up to two times (Allow preventDefault to be fired up to two times OneSignal-Android-SDK#2138)
• Recover null onesignal ID crashes for Operations (Recover null onesignal ID crashes for Operations OneSignal-Android-SDK#2157)
  *Prevent retrying IAM display if 410 is received from backend (Fix: Don't retry IAM display if 410 is received from backend OneSignal-Android-SDK#2158)

✨ Improvements

• Optimized the initialization process by moving some service initialization to a background thread ([Optimization] Init with context in background OneSignal-Android-SDK#2151)
• Add option to default to HMS over FCM (Add option to default to HMS over FCM OneSignal-Android-SDK#2163)
• Remove fallback code for FCM pre-21.0.0 (Remove fallback code for FCM pre-21.0.0 OneSignal-Android-SDK#2148)
• Clean up Android Support Library references, drop dependency on androidx.legacy, & Android 4.4 and older code (Clean up Android Support Library references, drop dependency on androidx.legacy, & Android 4.4 and older code OneSignal-Android-SDK#2147)

Update iOS SDK from 5.2.2 to 5.2.3 release notes

🐛 Bug Fixes

• The user executor needs to uncache first which fixes some cached requests being dropped for past users ([Bug] The user executor needs to uncache before other executors OneSignal-iOS-SDK#1465)

✨ Improvements

• Omit misleading fatal-level log for cross-platform SDKs (Omit misleading fatal-level log for wrappers OneSignal-iOS-SDK#1468)

🛠️ Maintenance

• [For our server] Use only OneSignal ID for requests ([Feat] Use only OneSignal ID for requests OneSignal-iOS-SDK#1464)

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