[dagit] Fix SearchBootstrapQuery to be lazy (#7981)

### Summary & Motivation

Make the global search dialog's bootstrap query be lazy (upon opening the search dialog) instead of loading it up front.

I had thought this was already lazy, but apparently not.

### How I Tested These Changes

Load Dagit, verify that no `SearchBootstrapQuery` is fired. Click "Search", verify that it is fired and that search behaves normally.

js_modules/dagit/packages/core/src/search/SearchDialog.tsx

@@ -59,15 +59,19 @@ const initialState: State = {
 export const SearchDialog: React.FC<{searchPlaceholder: string}> = ({searchPlaceholder}) => {
   const location = useLocation();
   const history = useHistory();
-  const {loading, performSearch} = useRepoSearch();
+  const {performBootstrapQuery, loading, performSearch} = useRepoSearch();
 
   const [state, dispatch] = React.useReducer(reducer, initialState);
   const {shown, queryString, results, highlight, loaded} = state;
 
   const renderedResults = results.slice(0, MAX_DISPLAYED_RESULTS);
   const numRenderedResults = renderedResults.length;
 
-  const openSearch = React.useCallback(() => dispatch({type: 'show-dialog'}), []);
+  const openSearch = React.useCallback(() => {
+    performBootstrapQuery();
+    dispatch({type: 'show-dialog'});
+  }, [performBootstrapQuery]);
+
   const onChange = React.useCallback((e) => {
     dispatch({type: 'change-query', queryString: e.target.value});
   }, []);

js_modules/dagit/packages/core/src/search/useRepoSearch.tsx

@@ -1,4 +1,4 @@
-import {gql, useLazyQuery, useQuery} from '@apollo/client';
+import {gql, useLazyQuery} from '@apollo/client';
 import Fuse from 'fuse.js';
 import * as React from 'react';
 
@@ -127,15 +127,15 @@ const secondaryDataToSearchResults = (data?: SearchSecondaryQuery) => {
 };
 
 export const useRepoSearch = () => {
-  const {data: bootstrapData, loading: bootstrapLoading} = useQuery<SearchBootstrapQuery>(
-    SEARCH_BOOTSTRAP_QUERY,
-    {
-      fetchPolicy: 'cache-and-network',
-    },
-  );
+  const [
+    performBootstrapQuery,
+    {data: bootstrapData, loading: bootstrapLoading},
+  ] = useLazyQuery<SearchBootstrapQuery>(SEARCH_BOOTSTRAP_QUERY, {
+    fetchPolicy: 'cache-and-network',
+  });
 
   const [
-    performQuery,
+    performSecondaryQuery,
     {data: secondaryData, loading: secondaryLoading, called: secondaryQueryCalled},
   ] = useLazyQuery<SearchSecondaryQuery>(SEARCH_SECONDARY_QUERY, {
     fetchPolicy: 'cache-and-network',
@@ -151,16 +151,16 @@ export const useRepoSearch = () => {
   const performSearch = React.useCallback(
     (queryString: string, buildSecondary?: boolean): Fuse.FuseResult<SearchResult>[] => {
       if ((queryString || buildSecondary) && !secondaryQueryCalled) {
-        performQuery();
+        performSecondaryQuery();
       }
       const bootstrapResults: Fuse.FuseResult<SearchResult>[] = bootstrapFuse.search(queryString);
       const secondaryResults: Fuse.FuseResult<SearchResult>[] = secondaryFuse.search(queryString);
       return [...bootstrapResults, ...secondaryResults];
     },
-    [bootstrapFuse, secondaryFuse, performQuery, secondaryQueryCalled],
+    [bootstrapFuse, secondaryFuse, performSecondaryQuery, secondaryQueryCalled],
   );
 
-  return {loading, performSearch};
+  return {performBootstrapQuery, loading, performSearch};
 };
 
 const SEARCH_BOOTSTRAP_QUERY = gql`