Fix crash when an app is being force quit
Fix crash when an app is being force quit

The SDK was expecting an active session to genegate a force quit message. Now the SDK will only generate the force quit message if there is an active session

mParticle/mparticle-apple-sdk,mParticle/mparticle-apple-sdk,mParticle/mParticle-iOS-SDK,mParticle/mParticle-iOS-SDK,mParticle/mparticle-apple-sdk,mParticle/mparticle-apple-sdk,mParticle/mparticle-apple-sdk,mParticle/mparticle-apple-sdk,mParticle/mParticle-iOS-SDK