fix(types): avoid inferring UiState type from initialUiState (#5061)

* fix(types): make all usages of UiState in InstantSearch generic

This allows someone with custom widgets to still use setUiState etc. without type errors

* fix lint

* fix(types): avoid inferring UiState type from initialUiState

if you pass initialUiState, that should be asserted by the generic UiState, not automatically accepted. Otherwise you get use cases like the "with function form sets indices state" test where setUiState thinks query is required, just because it has the default given

The way this works is by using `NoInfer` from microsoft/TypeScript#14829 (comment) which seems to be quite relied upon

This is a follow-up on #5060

src/lib/InstantSearch.ts

@@ -41,6 +41,11 @@ function defaultCreateURL() {
   return '#';
 }
 
+// this purposely breaks typescript's type inference to ensure it's not used
+// as it's used for a default parameter for example
+// source: https://github.com/Microsoft/TypeScript/issues/14829#issuecomment-504042546
+type NoInfer<T> = [T][T extends any ? 0 : never];
+
 /**
  * Global options for an InstantSearch instance.
  */
@@ -114,7 +119,7 @@ export type InstantSearchOptions<
    * for the first search. To unconditionally pass additional parameters to the
    * Algolia API, take a look at the `configure` widget.
    */
-  initialUiState?: TUiState;
+  initialUiState?: NoInfer<TUiState>;
 
   /**
    * Time before a search is considered stalled. The default is 200ms

src/lib/__tests__/InstantSearch-test.tsx

@@ -2681,7 +2681,9 @@ describe('onStateChange', () => {
 describe('initialUiState', () => {
   it('warns if UI state contains unmounted widgets in development mode', async () => {
     const searchClient = createSearchClient();
-    const search = new InstantSearch({
+    const search = new InstantSearch<
+      UiState & { [indexName: string]: { customWidget?: { query: string } } }
+    >({
       indexName: 'indexName',
       searchClient,
       initialUiState: {