[roll] Roll fuchsia [bt] Convert Status<hci_spec::StatusCode> to fitx::result<Error<hci_spec::StatusCode>>

Add alias hci::Error for bt::Error<hci_spec::StatusCode>.
Add alias hci::Result<…> for
fitx::result<bt::Error<hci_spec::StatusCode>, …>.
Add alias hci::ResultFunction<…> for
fit::function<void(fitx::result<bt::Error<hci_spec::StatusCode>, …>)>.

Replace hci::Status, hci::StatusCallback with hci::Result and
hci::ResultFunction<>, respectively.
In hci::Connection, refactor EnableEncryptionCallback to be
hci::ResultFunction<bool>, i.e. holds the success value in the result
parameter rather than a separate parameter. Other refactors are possible
but not performed as this particular change is a proof-of-concept.

In LowEnergyConnectionManager, LowEnergyConnectionRequest,
LowEnergyConnector, hci::CommandHandler, l2cap and transport classes
that have RequestAclPriority and SetBrEdrAutomaticFlushTimeout, convert
the use of fpromise::result to fitx::result. The fpromise::result
occurrences in l2cap::LogicalLink are kept because they are actually the
results of fpromise::promise computations.

Add HostErrorToFidl(bt::Error<…>) overload.
Add fpromise<void, f.b.s.Error> ResultToFidl(fitx::result<bt::Error<…>)
FIDL conversion helper.

Rename EventPacket::ToStatus to EventPacket::ToResult.
Add EventPacket::ToStatusCode for EncryptionKeyRefreshComplete, in order
to use it with hci_is_error and EventPacket.ToResult.

Where appropriate, rename some |status| identifiers to |result|.

Original-Bug: 86900, 90772
Test: fx test //src/connectivity/bluetooth
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/623783
Original-Revision: eb0a71a6164acf55e1d94cc14df3e223f940ad06
GitOrigin-RevId: 05a2640161cd18c453fac1efce01fbe2dce12ca2
Change-Id: Ic8c1356c47b309972f141abbfd62ce4f8bba2cd7