Migrate one-to-one-chat.spec.ts from Cypress to Playwright (#11953)

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

playwright/plugins/homeserver/index.ts

@@ -55,4 +55,5 @@ export interface Credentials {
     deviceId: string;
     homeServer: string;
     password: string | null; // null for password-less users
+    displayName?: string;
 }

playwright/plugins/homeserver/synapse/index.ts

@@ -193,6 +193,7 @@ export class Synapse implements Homeserver, HomeserverInstance {
             userId: data.user_id,
             deviceId: data.device_id,
             password,
+            displayName,
         };
     }
 }