feat(ui): improve scheduler selection logic

- remove UI-specific state (the enabled schedulers) from redux, instead derive it in a selector
- simplify logic by putting schedulers in an object instead of an array
- rename `activeSchedulers` to `enabledSchedulers`
- remove need for `useEffect()` when `enabledSchedulers` changes by adding a listener for the `enabledSchedulersChanged` action/event to `generationSlice`
- increase type safety by making `enabledSchedulers` an array of `SchedulerParam`, which is created by the zod schema for scheduler

invokeai/frontend/web/src/features/system/components/SettingsModal/SettingsSchedulers.tsx

@@ -1,30 +1,39 @@
-import { SCHEDULERS } from 'app/constants';
+import { SCHEDULER_SELECT_ITEMS } from 'app/constants';
 import { RootState } from 'app/store/store';
 
 import { useAppDispatch, useAppSelector } from 'app/store/storeHooks';
 import IAIMantineMultiSelect from 'common/components/IAIMantineMultiSelect';
-import { setSelectedSchedulers } from 'features/ui/store/uiSlice';
+import { SchedulerParam } from 'features/parameters/store/parameterZodSchemas';
+import { enabledSchedulersChanged } from 'features/ui/store/uiSlice';
+import { map } from 'lodash-es';
+import { useCallback } from 'react';
 import { useTranslation } from 'react-i18next';
 
+const data = map(SCHEDULER_SELECT_ITEMS).sort((a, b) =>
+  a.label.localeCompare(b.label)
+);
+
 export default function SettingsSchedulers() {
   const dispatch = useAppDispatch();
-
-  const selectedSchedulers = useAppSelector(
-    (state: RootState) => state.ui.selectedSchedulers
-  );
-
   const { t } = useTranslation();
 
-  const schedulerSettingsHandler = (v: string[]) => {
-    dispatch(setSelectedSchedulers(v));
-  };
+  const enabledSchedulers = useAppSelector(
+    (state: RootState) => state.ui.enabledSchedulers
+  );
+
+  const handleChange = useCallback(
+    (v: string[]) => {
+      dispatch(enabledSchedulersChanged(v as SchedulerParam[]));
+    },
+    [dispatch]
+  );
 
   return (
     <IAIMantineMultiSelect
       label={t('settings.availableSchedulers')}
-      value={selectedSchedulers}
-      data={SCHEDULERS}
-      onChange={schedulerSettingsHandler}
+      value={enabledSchedulers}
+      data={data}
+      onChange={handleChange}
       clearable
       searchable
       maxSelectedValues={99}