Fix NPEs on buffer line and windowsPty option

src/common/services/OptionsService.ts

@@ -178,12 +178,16 @@ export class OptionsService extends Disposable implements IOptionsService {
         if (value <= 0) {
           throw new Error(`${key} cannot be less than or equal to 0, value: ${value}`);
         }
+        break;
       case 'rows':
       case 'cols':
         if (!value && value !== 0) {
           throw new Error(`${key} must be numeric, value: ${value}`);
         }
         break;
+      case 'windowsPty':
+        value = value ?? {};
+        break;
     }
     return value;
   }