[REQUIRED] Step 1: Describe your environment

• Xcode version: 13.1
• Firebase SDK version: 8.10.0
• Installation method: Swift Package Manager
• Firebase Component: In-App Messaging
• Target platform(s): iOS

[REQUIRED] Step 2: Describe the problem

Duplicate messages can occur when two campaigns are triggered by different events. (The first message must have an image to reproduce it.)

Setup like this in the console.

First Event	Second Event

And trigger events consecutively like this code.

struct ContentView: View {
    var body: some View {
        Button("Trigger In-App") {
            InAppMessaging.inAppMessaging().triggerEvent("first_event")
            InAppMessaging.inAppMessaging().triggerEvent("second_event")
        }
            .padding()
    }
}

It shows multiple dialogs in a row.

It seems FIRIAMDisplayExecutor checks message is displayed or not in this code.

However, isMsgBeingDisplayed becomes true only after the image has finished loading.

I think if another event is triggered while loading the image in a first event, two dialogs are shown in the order in which the images were loaded.

And _currentMsgBeingDisplayed is set as last called displayForMessage. The last event(In this video, second event) may be treated as displayed.

Therefore, on the second tap in this video, it shows the first event.

I think the first tap will give me a first event message, and the second tap will give me a second event message.

Steps to reproduce:

• Set two campaigns with another event trigger and it has an image.
• Trigger events consecutively.

Minimum reproduce project is here: https://github.com/kouki-dan/InAppMessaging-Duplicate