Fix bubble layout in message details

TextView size depends on the VC.view size, so it must be updated when
view is done laying out.

// FREEBIE

Signal/src/ViewControllers/MessageDetailViewController.swift

@@ -89,6 +89,8 @@ class MessageDetailViewController: OWSViewController, UIScrollViewDelegate, Medi
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
 
+        updateTextLayout()
+
         if mode == .focusOnMetadata {
             if let bubbleView = self.bubbleView {
                 // Force layout.