[roll] Roll fuchsia [lint] Remove allow(clippy::large_futures) tags

Audit the codebase to fix large async future state machines and remove
all remaining clippy::large_futures lint suppressions outside
third_party.
- ascendd & socket-to-stdio: Removed redundant allow attributes from
  futures that are already < 16 KiB following prior refactorings
  (USB support removal and stack buffer heap conversion).
- vsockperf CLI: Replaced 4 KiB stack I/O buffers in read_single_stream
  and write_single_stream with heap vec! buffers. This reduces the
  multi-stream try_join! future state machine by ~20 KiB without
  affecting streaming loop latency.
- stream_processors: Boxed slow-path BufferSetFactory::buffer_set
  allocations (Box::pin(...).await) in Stream::handle_event, preventing
  ~24 KiB sysmem2 FIDL buffer setup structs from bloating stream runner
  task stacks.

Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1768475
Original-Original-Revision: 9261277323b13efd66d4bd369149e2778b1c24f0
GitOrigin-RevId: 90089f690d756826ead1651c2cdc391aa682bcfd
Change-Id: I8752b2d37daa055010bfe0e4564407a92ac758bd
Reviewed-on: https://fuchsia-review.googlesource.com/c/integration/+/1773253
Cr-Commit-Position: refs/heads/main@{#199876}