[fidl] Migrate error syntax to fitx::result

This change converts all the FIDL result producing
methods/operators (`.Unwrap()`, `.value()`, `->`, `*`) to their
`fitx::result` producing equivalents (`.Unwrap_NEW()` and
`.value_NEW()`).

Bug: 93988
Test: fx build; fx test; fx lsc presubmit
Change-Id: Ic5709baf1fc2d176b0d15248803a7c5dfad19280
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/openssh-portable/+/675863
Commit-Queue: Alex Zaslavsky <azaslavsky@google.com>
Reviewed-by: Yifei Teng <yifeit@google.com>
diff --git a/fuchsia/fuchsia-pty.cc b/fuchsia/fuchsia-pty.cc
index 8223152..9292062 100644
--- a/fuchsia/fuchsia-pty.cc
+++ b/fuchsia/fuchsia-pty.cc
@@ -32,15 +32,15 @@
     fprintf(stderr, "Failed to open PTY client: %s\n", endpoints.status_string());
     return -1;
   }
-  auto result =
-      fidl::WireCall(caller.borrow_as<fpty::Device>())->OpenClient(id, std::move(endpoints->server));
+  auto result = fidl::WireCall(caller.borrow_as<fpty::Device>())
+                    ->OpenClient(id, std::move(endpoints->server));
 
   if (result.status() != ZX_OK) {
     fprintf(stderr, "Failed to open PTY client: %s\n", zx_status_get_string(result.status()));
     return -1;
   }
-  if (result->s != ZX_OK) {
-    fprintf(stderr, "Failed to open PTY client: %s\n", zx_status_get_string(result->s));
+  if (result.value().s != ZX_OK) {
+    fprintf(stderr, "Failed to open PTY client: %s\n", zx_status_get_string(result.value().s));
     return -1;
   }