Disable clang-analyzer-security.ArrayBound warning in PromiseDisposer::append
to silence clang-tidy.

A new clang-analyzer-security.ArrayBound "warning: Out of bound access to
memory preceding the region" "note: Access of the region at negative byte
offset -112" started happening when updating from clang-tidy 20 to 21.

The warning doesn't seem to indicate a real problem because ChainPromiseNode
instances which inherit from PromiseArenaMember are constructed starting at the
end of the PromiseArray byte array and a bounds check is done right before
calling the constructor.

More information the warning can be found:

- https://clang.llvm.org/docs/analyzer/checkers.html#security-arraybound-c-c
- bitcoin/bitcoin#33445 (comment)

Error output looks like:

/usr/include/kj/async-inl.h:404:12: warning: Out of bound access to memory preceding the region [clang-analyzer-security.ArrayBound]
  404 |       ctor(*ptr, kj::mv(next), kj::fwd<Params>(params)...);
      |            ^
[...]
/home/admin/actions-runner/_work/_temp/src/ipc/libmultiprocess/include/mp/type-context.h:146:12: note: Calling 'Promise::then'
[...]
/usr/include/kj/async-inl.h:1301:7: note: Calling 'maybeChain<capnp::CallContext<ipc::capnp::messages::BlockTemplate::WaitNextParams, ipc::capnp::messages::BlockTemplate::WaitNextResults>>'
 1301 |       _::maybeChain(kj::mv(intermediate), implicitCast<ResultT*>(nullptr), location));
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/kj/async-inl.h:955:10: note: Calling 'appendPromise<kj::_::ChainPromiseNode, kj::SourceLocation &>'
  955 |   return appendPromise<ChainPromiseNode>(kj::mv(node), location);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/kj/async-inl.h:454:10: note: Calling 'PromiseDisposer::append'
  454 |   return PromiseDisposer::append<T>(kj::mv(next), kj::fwd<Params>(params)...);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/kj/async-inl.h:389:9: note: Left side of '||' is false
  389 |     if (!canArenaAllocate<T>() || arena == nullptr ||
      |         ^
/usr/include/kj/async-inl.h:389:9: note: Left side of '||' is false
/usr/include/kj/async-inl.h:390:9: note: Assuming the condition is false
  390 |         reinterpret_cast<byte*>(next.get()) - reinterpret_cast<byte*>(arena) < sizeof(T)) {
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/kj/async-inl.h:389:5: note: Taking false branch
  389 |     if (!canArenaAllocate<T>() || arena == nullptr ||
      |     ^
/usr/include/kj/async-inl.h:404:12: note: Access of the region at negative byte offset -112
  404 |       ctor(*ptr, kj::mv(next), kj::fwd<Params>(params)...);
      |            ^~~~