sign in copy change (#1249)

assets/l10n/intl_en.arb

@@ -4624,6 +4624,7 @@
       "maxXP": {}
     }
   },
+  "signInWithUsername": "Sign in with username and password",
   "registrationEmailMessage": "Please verify your email with a link sent there. In some cases, the email takes up to 5 minutes to arrive. Please also check your spam folder.",
   "enableTTSToolName": "Enabled text-to-speech",
   "enableTTSToolDescription": "Allow the app to generate text-to-speech output for portions of text in your target language",

lib/pages/homeserver_picker/homeserver_picker_view.dart

@@ -146,7 +146,7 @@ class HomeserverPickerView extends StatelessWidget {
                                             horizontal: 10,
                                           ),
                                           child: Text(
-                                            "${L10n.of(context).loginOrSignup} Pangea Chat",
+                                            L10n.of(context).signInWithUsername,
                                           ),
                                         ),
                                       ],