Prevent double-push of edit username screen

RELEASE-NOTES.txt

@@ -1,6 +1,6 @@
 19.1
 -----
-
+* [*] Signup: Fixed bug where username selection screen could be pushed twice. [#17624]
 
 19.0
 -----

WordPress/Classes/ViewRelated/NUX/SignupEpilogueCell.swift

@@ -5,7 +5,6 @@ import WordPressAuthenticator
 protocol SignupEpilogueCellDelegate {
     func updated(value: String, forType: EpilogueCellType)
     func changed(value: String, forType: EpilogueCellType)
-    func usernameSelected()
 }
 
 enum EpilogueCellType: Int {
@@ -105,6 +104,7 @@ class SignupEpilogueCell: UITableViewCell {
         configureAccessoryType(for: newCellType)
         configureTextContentTypeIfNeeded(for: newCellType)
         configureAccessibility(for: newCellType)
+        configureEditable(for: newCellType)
 
         addBottomBorder(withColor: .divider, leadingMargin: cellLabelLeadingConstraint.constant)
 
@@ -137,15 +137,6 @@ extension SignupEpilogueCell: UITextFieldDelegate {
         }
     }
 
-    func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
-        if let cellType = cellType,
-            cellType == .username {
-            delegate?.usernameSelected()
-            return false
-        }
-        return true
-    }
-
     func textFieldShouldReturn(_ textField: UITextField) -> Bool {
         cellField.endEditing(true)
         return true
@@ -210,4 +201,12 @@ private extension SignupEpilogueCell {
         }
     }
 
+    func configureEditable(for cellType: EpilogueCellType) {
+        if cellType == .username {
+            cellField.isEnabled = false
+        } else {
+            cellField.isEnabled = true
+        }
+    }
+
 }

WordPress/Classes/ViewRelated/NUX/SignupEpilogueTableViewController.swift

@@ -139,6 +139,13 @@ class SignupEpilogueTableViewController: UITableViewController, EpilogueUserInfo
         return UITableView.automaticDimension
     }
 
+    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
+        if let cellType = EpilogueCellType(rawValue: indexPath.row),
+           cellType == .username {
+            delegate?.usernameTapped(userInfo: epilogueUserInfo)
+        }
+    }
+
 }
 
 // MARK: - Private Extension
@@ -275,8 +282,4 @@ extension SignupEpilogueTableViewController: SignupEpilogueCellDelegate {
         }
     }
 
-    func usernameSelected() {
-        delegate?.usernameTapped(userInfo: epilogueUserInfo)
-    }
-
 }