[ES|QL] Makes the clear control button optional (#212848)

## Summary

Closes https://github.com/elastic/kibana/issues/212605

Here we are removing the clear button from the ES|QL control as clearing
will result in wrong charts. I also considered the reset but when there
is no changes should be hidden or disabled. This seems to me as a
smaller change and taken under consideration that dashboard already
allows resetting I think it is ok to remove it.

We can always reconsider if any user complains.

Although by removing the clearSelections from the control config removes
the button the `DefaultControlApi ` was marking it as required. So I had
to tweak a bit the types.

examples/controls_example/public/app/control_group_renderer_examples/search_example.tsx

@@ -180,7 +180,7 @@ export const SearchExample = ({ data, dataView, navigation }: Props) => {
           onClick={() => {
             if (controlGroupAPI) {
               Object.values(controlGroupAPI.children$.getValue()).forEach((controlApi) => {
-                (controlApi as DefaultControlApi)?.clearSelections();
+                (controlApi as DefaultControlApi)?.clearSelections?.();
               });
             }
           }}

src/platform/plugins/shared/controls/public/controls/esql_control/get_esql_control_factory.tsx

@@ -96,9 +96,6 @@ export const getESQLControlFactory = (): ControlFactory<ESQLControlState, ESQLCo
               references: [],
             };
           },
-          clearSelections: () => {
-            // do nothing, not allowed for now;
-          },
         },
         {
           ...defaultControl.comparators,

src/platform/plugins/shared/controls/public/controls/types.ts

@@ -36,7 +36,7 @@ export type DefaultControlApi = PublishesDataLoading &
   PublishesBlockingError &
   PublishesUnsavedChanges &
   Partial<PublishesTitle & PublishesDisabledActionIds & HasCustomPrepend> &
-  CanClearSelections &
+  Partial<CanClearSelections> &
   HasType &
   HasUniqueId &
   HasSerializableState<DefaultControlState> &