Avoid !! in ResourceDrawableHelper.kt (facebook#43820)

Summary:
Pull Request resolved: facebook#43820

Changelog: [Internal]

Reviewed By: cortinico

Differential Revision: D55701291

fbshipit-source-id: afdce3ffa59bc488d6c36d78a8cf3176089599ba

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/imagehelper/ResourceDrawableIdHelper.kt

@@ -37,15 +37,16 @@ public class ResourceDrawableIdHelper private constructor() {
     }
 
     synchronized(this) {
-      if (resourceDrawableIdMap.containsKey(normalizedName)) {
-        return resourceDrawableIdMap.get(normalizedName)!!
-      }
-      return context.resources.getIdentifier(normalizedName, "drawable", context.packageName).also {
-        resourceDrawableIdMap[normalizedName] = it
-      }
+      return resourceDrawableIdMap.get(normalizedName) ?: addDrawableId(context, normalizedName)
     }
   }
 
+  private fun addDrawableId(context: Context, normalizedName: String): Int {
+    val newId = context.resources.getIdentifier(normalizedName, "drawable", context.packageName)
+    resourceDrawableIdMap[normalizedName] = newId
+    return newId
+  }
+
   public fun getResourceDrawable(context: Context, name: String?): Drawable? {
     val resId = getResourceDrawableId(context, name)
     return if (resId > 0) ResourcesCompat.getDrawable(context.resources, resId, null) else null