Fix reporting long background app startup spans (#524)

Co-authored-by: Robert Bartoszewski <robert.smartbear@gmail.com>

Author: robert-smartbear

Sources/BugsnagPerformance/Private/Instrumentation/AppStartupInstrumentation.mm

@@ -20,6 +20,7 @@
 
 using namespace bugsnag;
 
+static constexpr CFTimeInterval kMaxDurationFromLaunchToActive = 5;
 static constexpr CFTimeInterval kMaxDuration = 120;
 
 static CFAbsoluteTime getProcessStartTime() noexcept;
@@ -181,6 +182,12 @@ static inline bool isActivePrewarm(void) {
         return;
     }
     shouldRespondToAppDidBecomeActive_ = false;
+    
+    if (CFAbsoluteTimeGetCurrent() > didFinishLaunchingAtTime_ + kMaxDurationFromLaunchToActive) {
+        abortAllSpans();
+        isEnabled_ = false;
+        return;
+    }
 
     didBecomeActiveAtTime_ = CFAbsoluteTimeGetCurrent();
     [[BugsnagPerformanceCrossTalkAPI sharedInstance] willEndUIInitSpan:uiInitSpan_];