Fix fetching Nav fallback ID flushing Navigation entity cache (#52069)

* Only flush the `getEntityRecords` cache if the fallback isn’t already in state

* Save the edited entity record to a const and then invert it to determine whether we should invalidate the recordds

---------

Co-authored-by: scruffian <ben@scruffian.com>

packages/core-data/src/resolvers.js

@@ -573,7 +573,7 @@ export const getBlockPatternCategories =
 
 export const getNavigationFallbackId =
  () =>
- async ( { dispatch } ) => {
+ async ( { dispatch, select } ) => {
  const fallback = await apiFetch( {
  path: addQueryArgs( '/wp-block-editor/v1/navigation-fallback', {
  _embed: true,
@@ -585,8 +585,15 @@ export const getNavigationFallbackId =
  dispatch.receiveNavigationFallbackId( fallback?.id );
 
  if ( record ) {
- const invalidateNavigationQueries = true;
-
+ // If the fallback is already in the store, don't invalidate navigation queries.
+ // Otherwise, invalidate the cache for the scenario where there were no Navigation
+ // posts in the state and the fallback created one.
+ const existingFallbackEntityRecord = select.getEntityRecord(
+ 'postType',
+ 'wp_navigation',
+ fallback?.id
+ );
+ const invalidateNavigationQueries = ! existingFallbackEntityRecord;
  dispatch.receiveEntityRecords(
  'postType',
  'wp_navigation',