Paste an image into an edited message instead of sending a new copy

Fixes #13636

Author: Charlie Finlayson

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationFragment.kt

@@ -3786,7 +3786,7 @@ class ConversationFragment :
         body = result.body,
         mentions = result.mentions,
         bodyRanges = result.bodyRanges,
-        messageToEdit = null,
+        messageToEdit = inputPanel.editMessageId,
         quote = if (result.isViewOnce) null else inputPanel.quote.orNull(),
         scheduledDate = result.scheduledTime,
         slideDeck = null,