Restore initiallyFocusedItemKey for auto-scroll on mount

Re-adds initiallyFocusedItemKey so the list scrolls to the first
preselected item when opening the page. This does not cause scroll
jumps on item selection because FlashList's initialScrollIndex only
applies on mount and useArrowKeyFocusManager ignores prop changes
after its initial useState call.

Co-authored-by: mkhutornyi <mkhutornyi@users.noreply.github.com>

Author: MelvinBot

src/components/Search/SearchMultipleSelectionPicker.tsx

@@ -47,6 +47,7 @@ function SearchMultipleSelectionPicker<T extends string | string[]>({
 
     sectionData.sort((a, b) => sortOptionsWithEmptyValue(a.value.toString(), b.value.toString(), localeCompare));
 
+    const firstSelectedKey = sectionData.find((item) => item.isSelected)?.keyForList;
     const noResultsFound = !sectionData.length;
     const sections = noResultsFound
         ? []
@@ -93,6 +94,7 @@ function SearchMultipleSelectionPicker<T extends string | string[]>({
         <SelectionListWithSections
             sections={sections}
             ListItem={MultiSelectListItem}
+            initiallyFocusedItemKey={firstSelectedKey}
             shouldClearInputOnSelect={false}
             shouldShowTextInput={shouldShowTextInput}
             textInputOptions={textInputOptions}