msglist: Update label to "Messages with yourself" in DM header

Related CZO Discussion:
https://chat.zulip.org/#narrow/channel/137-feedback/topic/Chat.20with.20myself/with/2086462

Fixes: #1319

Author: lakshya1goel

assets/l10n/app_en.arb

@@ -404,7 +404,7 @@
       "others": {"type": "String", "example": "Alice, Bob"}
     }
   },
-  "messageListGroupYouWithYourself": "You with yourself",
+  "messageListGroupYouWithYourself": "Messages with yourself",
   "@messageListGroupYouWithYourself": {
     "description": "Message list recipient header for a DM group that only includes yourself."
   },

lib/generated/l10n/zulip_localizations.dart

@@ -630,7 +630,7 @@ abstract class ZulipLocalizations {
   /// Message list recipient header for a DM group that only includes yourself.
   ///
   /// In en, this message translates to:
-  /// **'You with yourself'**
+  /// **'Messages with yourself'**
   String get messageListGroupYouWithYourself;
 
   /// Content validation error message when the message is too long.

lib/generated/l10n/zulip_localizations_ar.dart

@@ -316,7 +316,7 @@ class ZulipLocalizationsAr extends ZulipLocalizations {
   }
 
   @override
-  String get messageListGroupYouWithYourself => 'You with yourself';
+  String get messageListGroupYouWithYourself => 'Messages with yourself';
 
   @override
   String get contentValidationErrorTooLong => 'Message length shouldn\'t be greater than 10000 characters.';

lib/generated/l10n/zulip_localizations_en.dart

@@ -316,7 +316,7 @@ class ZulipLocalizationsEn extends ZulipLocalizations {
   }
 
   @override
-  String get messageListGroupYouWithYourself => 'You with yourself';
+  String get messageListGroupYouWithYourself => 'Messages with yourself';
 
   @override
   String get contentValidationErrorTooLong => 'Message length shouldn\'t be greater than 10000 characters.';

lib/generated/l10n/zulip_localizations_ja.dart

@@ -316,7 +316,7 @@ class ZulipLocalizationsJa extends ZulipLocalizations {
   }
 
   @override
-  String get messageListGroupYouWithYourself => 'You with yourself';
+  String get messageListGroupYouWithYourself => 'Messages with yourself';
 
   @override
   String get contentValidationErrorTooLong => 'Message length shouldn\'t be greater than 10000 characters.';

lib/generated/l10n/zulip_localizations_nb.dart

@@ -316,7 +316,7 @@ class ZulipLocalizationsNb extends ZulipLocalizations {
   }
 
   @override
-  String get messageListGroupYouWithYourself => 'You with yourself';
+  String get messageListGroupYouWithYourself => 'Messages with yourself';
 
   @override
   String get contentValidationErrorTooLong => 'Message length shouldn\'t be greater than 10000 characters.';

lib/generated/l10n/zulip_localizations_sk.dart

@@ -316,7 +316,7 @@ class ZulipLocalizationsSk extends ZulipLocalizations {
   }
 
   @override
-  String get messageListGroupYouWithYourself => 'You with yourself';
+  String get messageListGroupYouWithYourself => 'Messages with yourself';
 
   @override
   String get contentValidationErrorTooLong => 'Message length shouldn\'t be greater than 10000 characters.';

lib/widgets/message_list.dart

@@ -1179,7 +1179,6 @@ class DmRecipientHeader extends StatelessWidget {
         .sorted()
         .join(", "));
     } else {
-      // TODO pick string; web has glitchy "You and $yourname"
       title = zulipLocalizations.messageListGroupYouWithYourself;
     }