improve(extension/schema-errors): remove is-error utility (#1193)

Author: jasonkuhrt

src/entrypoints/extensions.ts

@@ -1,4 +1,5 @@
 export { Introspection } from '../layers/7_extensions/Introspection/Introspection.js'
 export { Opentelemetry } from '../layers/7_extensions/Opentelemetry/Opentelemetry.js'
+export { SchemaErrors } from '../layers/7_extensions/SchemaErrors/SchemaErrors.js'
 export { Throws } from '../layers/7_extensions/Throws/Throws.js'
 export { Upload } from '../layers/7_extensions/Upload/Upload.js'