🎨 [open-formulieren/open-forms#4929] Small code improvements

* Take out the component-invariant function and move it to the module
  level. This gives it a stable reference as it doesn't depend on
  any components state or props.
* Throw errors instead of just logging them for a more obvious error
  handling flow.

Author: sergei-maertens

src/components/Summary/SubmissionSummary.jsx

@@ -12,7 +12,6 @@ import {findPreviousApplicableStep} from 'components/utils';
 import useFormContext from 'hooks/useFormContext';
 import useRefreshSubmission from 'hooks/useRefreshSubmission';
 import useTitle from 'hooks/useTitle';
-import Types from 'types';
 
 import GenericSummary from './GenericSummary';
 import {loadSummaryData} from './utils';
@@ -21,6 +20,17 @@ const initialState = {
   error: '',
 };
 
+const completeSubmission = async (submission, statementValues) => {
+  const response = await post(`${submission.url}/_complete`, statementValues);
+  if (!response.ok) {
+    console.error(response.data);
+    // TODO Specific error for each type of invalid data?
+    throw new Error('InvalidSubmissionData');
+  } else {
+    return response.data;
+  }
+};
+
 const reducer = (draft, action) => {
   switch (action.type) {
     case 'ERROR': {
@@ -53,10 +63,8 @@ const SubmissionSummary = ({processingError = '', onConfirm, onClearProcessingEr
     const submissionUrl = new URL(refreshedSubmission.url);
     return await loadSummaryData(submissionUrl);
   }, [refreshedSubmission.url]);
-
-  if (error) {
-    console.error(error);
-  }
+  // throw to nearest error boundary
+  if (error) throw error;
 
   const onSubmit = async statementValues => {
     if (refreshedSubmission.submissionAllowed !== SUBMISSION_ALLOWED.yes) return;
@@ -82,17 +90,6 @@ const SubmissionSummary = ({processingError = '', onConfirm, onClearProcessingEr
     navigate(getPreviousPage());
   };
 
-  const completeSubmission = async (submission, statementValues) => {
-    const response = await post(`${submission.url}/_complete`, statementValues);
-    if (!response.ok) {
-      console.error(response.data);
-      // TODO Specific error for each type of invalid data?
-      throw new Error('InvalidSubmissionData');
-    } else {
-      return response.data;
-    }
-  };
-
   const pageTitle = intl.formatMessage({
     description: 'Summary page title',
     defaultMessage: 'Check and confirm',