message: simplify moveBlock
diff: @@ -236,27 +236,11 @@ export const usePaginatedBlocks = (unsafeArgs: {
  */
  const moveBlock: UsePaginatedBlocksApi['moveBlock'] = useCallback(
  ({ oldIndex, newIndex }) => {
  - updateCache(({ blockArgs: [prevBlocks, { readField }] }) => {
  - // Read the current contentCount of the channel instead
  - // of passing it in as a useCallback dependency to reduce
  - // re renders
  - const count = client.readFragment<ChannelContentsCount>({
  - fragment: channelContentsCount,
  - id: client.cache.identify({
  - id: args.current.channelId,
  - __typename: 'Channel',
  - }),
  - })?.counts?.contents
  -
  - // Early exit if we can't read the count
  - if (!count) {
  - return null
  - }
  -
  + updateCache(({ blockArgs: [prevBlocks, { readField }], prevCount }) => {
  // Moving to the "bottom". Convert a -1 newIndex value to a
  // synonymous "count - 1" value that the mutation can understand
  if (newIndex === -1) {
  - newIndex = count - 1
  + newIndex = prevCount - 1
  }
  // Get the block reference in the cache. Early exit if we can't
  @@ -288,7 +272,7 @@ export const usePaginatedBlocks = (unsafeArgs: {
  typename as ChannelContentsConnectable['__typename']
  ),
  },
  - insert_at: count - newIndex,
  + insert_at: prevCount - newIndex,
  },
  })
  