build: enable skipLibCheck TS config option

This allows ignoring the error that is thrown due to the incompatibility
of the typings in `resize-observer-polyfill` version <=1.5.1 with
TypeScript version >=4.2. See also:
- https://circleci.com/gh/angular/ngcc-validation/28399
- que-etc/resize-observer-polyfill#80

Besides that, setting `skipLibCheck` to `true` is a recommended setting
and will avoid unnecessary work.

infra/failing-projects.json

@@ -1,20 +1,10 @@
 {
   "es2015": [
     "nativescript-angular-ngcc",
-    "nebularauth-ngcc",
-    "nebulardate-fns-ngcc",
-    "nebulareva-icons-ngcc",
-    "nebularmoment-ngcc",
-    "nebulartheme-ngcc",
     "ng6-breadcrumbs-ngcc"
   ],
   "es5": [
     "nativescript-angular-ngcc",
-    "nebularauth-ngcc",
-    "nebulardate-fns-ngcc",
-    "nebulareva-icons-ngcc",
-    "nebularmoment-ngcc",
-    "nebulartheme-ngcc",
     "ng6-breadcrumbs-ngcc"
   ]
 }

tsconfig.base.json

@@ -11,6 +11,7 @@
     "module": "es2020",
     "moduleResolution": "node",
     "importHelpers": true,
+    "skipLibCheck": true,
     "target": "es5",
     "typeRoots": [
       "node_modules/@types"