Add warning when adding a caption.

libraries/featureflag/api/src/main/kotlin/io/element/android/libraries/featureflag/api/FeatureFlags.kt

@@ -144,7 +144,14 @@ enum class FeatureFlags(
         key = "feature.media_caption_creation",
         title = "Allow creation of media captions",
         description = null,
-        defaultValue = { buildMeta -> buildMeta.buildType != BuildType.RELEASE },
+        defaultValue = { true },
+        isFinished = false,
+    ),
+    MediaCaptionWarning(
+        key = "feature.media_caption_creation_warning",
+        title = "Show a compatibility warning on media captions creation",
+        description = null,
+        defaultValue = { true },
         isFinished = false,
     ),
 }