chore: fix type issues

packages/form-core/test-suites/form-group/FormGroupMixin.suite.js

@@ -1,4 +1,4 @@
-import { ifDefined, LitElement } from '@lion/core';
+import { LitElement } from '@lion/core';
 import { IsNumber, LionField, Validator } from '@lion/form-core';
 import '@lion/form-core/define';
 import { localizeTearDown } from '@lion/localize/test-helpers';
@@ -1387,8 +1387,8 @@ export function runFormGroupMixinSuite(cfg = {}) {
         render() {
           return html`
               <${tag}
-              .modelValue=${ifDefined(this.modelValue)}
-              .serializedValue=${ifDefined(this.serializedValue)}>
+              .modelValue=${this.modelValue}
+              .serializedValue=${this.serializedValue}>
                 ${this.fields.map(field => {
                   if (typeof field === 'object') {
                     return html`<${childTag} name="${field.name}" .modelValue="${field.value}"></${childTag}>`;

tsconfig.json

@@ -12,7 +12,8 @@
     "alwaysStrict": true,
     "types": ["node", "mocha", "sinon"],
     "esModuleInterop": true,
-    "suppressImplicitAnyIndexErrors": true
+    "suppressImplicitAnyIndexErrors": true,
+    "skipLibCheck": true
   },
   "include": ["packages/**/*.js", "packages-node/**/*.js"],
   "exclude": [