Add fnr validation component

frontend/src/components/form/fnr.tsx

 import React from 'react'
 import validator from '@navikt/fnrvalidator'
-import { UseFormReturn } from "react-hook-form";
+import { UseFormReturn } from 'react-hook-form'
 
 export function isValidIdnr(data: string) {
-    const validationResult = validator.idnr(data)
-    return validationResult.status === "valid"
+  const validationResult = validator.idnr(data)
+  return validationResult.status === 'valid'
 }
 
-interface FnrProps
-    extends Partial<Pick<UseFormReturn, "register">> {
-    name: string
-    label?: string
-    errors?: any
+interface FnrProps extends Partial<Pick<UseFormReturn, 'register'>> {
+  name: string
+  errors?: any
 }
 
-export default function Fnr(props: FnrProps) {
-    const { register, name, errors, ...rest } = props
-    if (register === undefined) {
-        return <></>
-    }
+function Fnr(props: FnrProps) {
+  const { register, name, errors } = props
+  if (register === undefined) {
+    return <></>
+  }
 
-    return <>
-        <input type="text"
-          placeholder={name}
-          {...register(name, { required: "Fnr is required", validate: isValidIdnr })}
-          id="fnr"
-        />
-        {errors.fnr && errors.fnr.message}
-        {errors.fnr && errors.fnr.type === "validate" && 'Invalid fnr'}
+  return (
+    <>
+      <input
+        type="text"
+        placeholder={name}
+        // eslint-disable-next-line react/jsx-props-no-spreading
+        {...register(name, {
+          required: 'Fnr is required',
+          validate: isValidIdnr,
+        })}
+        id="fnr"
+      />
+      {errors.fnr && errors.fnr.message}
+      {errors.fnr && errors.fnr.type === 'validate' && 'Invalid fnr'}
     </>
+  )
+}
 
+Fnr.defaultProps = {
+  errors: {},
 }
 
+export default Fnr