Memory leak in FirebaseInAppMessagingDisplay

### [READ] Step 1: Are you in the right place?

Yes

### [REQUIRED] Step 2: Describe your environment

* Android Studio version: Android Studio Flamingo | 2022.2.1 Patch 2
* Firebase Component: firebase-inappmessaging-display
* Component version: 20.3.2

### [REQUIRED] Step 3: Describe the problem

#### Steps to reproduce:

Install LeakCanary and Firebase In App Messaging in the project. Launch the app. Wait for the leak notification to appear.
LeakCanary is reporting a memory leak for FirebaseInAppMessagingDisplay. Here is part of the leak report:

```
┬───
│ GC Root: System class
│
├─ android.provider.FontsContract class
│ Leaking: NO (DriverApplication↓ is not leaking and a class is never leaking)
│ ↓ static FontsContract.sContext
├─ some.app.DriverApplication instance
│ Leaking: NO (Application is a singleton)
│ mBase instance of android.app.ContextImpl
│ ↓ Application.mActivityLifecycleCallbacks
│ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
├─ java.util.ArrayList instance
│ Leaking: UNKNOWN
│ Retaining 403 B in 19 objects
│ ↓ ArrayList[4]
│ ~~~
├─ com.google.firebase.inappmessaging.display.FirebaseInAppMessagingDisplay instance
│ Leaking: UNKNOWN
│ Retaining 456.4 kB in 8619 objects
│ application instance of some.app.DriverApplication
│ ↓ FirebaseInAppMessagingDisplay.imageLoader
│ ~~~~~~~~~~~
├─ com.google.firebase.inappmessaging.display.internal.FiamImageLoader instance
│ Leaking: UNKNOWN
│ Retaining 455.5 kB in 8584 objects
│ ↓ FiamImageLoader.tags
│ ~~~~
├─ java.util.HashMap instance
│ Leaking: UNKNOWN
│ Retaining 455.5 kB in 8583 objects
│ ↓ HashMap["HomeActivity"]
│ ~~~~~~~~~~~~~~~~
├─ java.util.HashSet instance
│ Leaking: UNKNOWN
│ Retaining 447.5 kB in 8434 objects
│ ↓ HashSet[element()]
│ ~~~~~~~~~~~
├─ com.google.firebase.inappmessaging.display.FirebaseInAppMessagingDisplay$4 instance
│ Leaking: UNKNOWN
│ Retaining 447.4 kB in 8430 objects
│ Anonymous subclass of com.google.firebase.inappmessaging.display.internal.FiamImageLoader$Callback
│ val$activity instance of some.app.home.HomeActivity with mDestroyed = true
│ ↓ FirebaseInAppMessagingDisplay$4.val$activity
│ ~~~~~~~~~~~~
╰→ some.app.home.HomeActivity instance
​ Leaking: YES (ObjectWatcher was watching this because some.app.home.HomeActivity received
​ Activity#onDestroy() callback and Activity#mDestroyed is true)
​ Retaining 440.0 kB in 8306 objects
​ key = f3ad578b-7adc-416f-87d8-46bbb060e66e
​ watchDurationMillis = 5454
​ retainedDurationMillis = 454
​ mApplication instance of some.app.DriverApplication
​ mBase instance of androidx.appcompat.view.ContextThemeWrapper

METADATA

Build.VERSION.SDK_INT: 33
Build.MANUFACTURER: Google
LeakCanary version: 2.11
App process name: some.app
Class count: 35245
Instance count: 248240
Primitive array count: 158202
Object array count: 37703
Thread count: 91
Heap total bytes: 34959895
Bitmap count: 30
Bitmap total bytes: 766474
Large bitmap count: 0
Large bitmap total bytes: 0
Db 1: open /data/user/0/some.app/databases/com.google.android.datatransport.events
Db 2: closed /data/user/0/some.app/databases/google_app_measurement_local.db
Db 3: open /data/user/0/some.app/no_backup/androidx.work.workdb
Db 4: open /data/user/0/some.app/databases/leaks.db
Db 5: closed /data/user/0/some.app/databases/google_app_measurement_local.db
Db 6: closed /data/user/0/some.app/databases/google_app_measurement_local.db
Db 7: closed /data/user/0/some.app/databases/google_app_measurement_local.db
Db 8: closed /data/user/0/some.app/databases/google_app_measurement_local.db
Count of retained yet cleared: 14 KeyedWeakReference instances
Stats: LruCache[maxSize=3000,hits=123669,misses=242264,hitRate=33%]
RandomAccess[bytes=12113847,reads=242264,travel=105517108805,range=41605070,size=50779357]
Analysis duration: 18044 ms

```