Turned off autocomplete in Search input field

close https://linear.app/ghost/issue/AP-612/autofill-appears-in-searchfield

- Safari autocompletes our Search field because it mentions the word 'username' in the placeholder text, but we don't want that as users don't really want to search for their own usernames.

apps/admin-x-activitypub/src/components/Search.tsx

@@ -151,6 +151,7 @@ const Search: React.FC<SearchProps> = ({}) => {
                 <div className='relative flex w-full items-center'>
                     <Icon className='absolute left-3 top-3 z-10' colorClass='text-grey-500' name='magnifying-glass' size='sm' />
                     <TextField
+                        autoComplete='off'
                         className='mb-6 mr-12 flex h-10 w-full items-center rounded-lg border border-transparent bg-grey-100 px-[33px] py-1.5 transition-colors focus:border-green focus:bg-white focus:outline-2 dark:border-transparent dark:bg-grey-925 dark:text-white dark:placeholder:text-grey-800 dark:focus:border-green dark:focus:bg-grey-950 tablet:mr-0'
                         containerClassName='w-100'
                         inputRef={queryInputRef}