GH-32206: [C++] GcsFileSystem::Make should return Result (#44503)

### What changes are included in this PR?

GcsFileSystem::Make now returns Result, with corresponding header & test changes.

### Are these changes tested?

Yes, `arrow-gcsfs-test` passed.

### Are there any user-facing changes?

Yes.

**This PR includes breaking changes to public APIs.**

* GitHub Issue: #32206

Lead-authored-by: Gabriel Stone <Gabe.Stone@ibm.com>
Co-authored-by: Gabriel P Stone <Gabe.Stone@ibm.com>
Co-authored-by: Gabriel P Stone <gpstone@acm.org>
Co-authored-by: Sutou Kouhei <kou@cozmixng.org>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>

cpp/src/arrow/filesystem/gcsfs.cc

@@ -962,10 +962,11 @@ Result<std::shared_ptr<io::OutputStream>> GcsFileSystem::OpenAppendStream(
   return Status::NotImplemented("Append is not supported in GCS");
 }
 
-std::shared_ptr<GcsFileSystem> GcsFileSystem::Make(const GcsOptions& options,
-                                                   const io::IOContext& context) {
+Result<std::shared_ptr<GcsFileSystem>> GcsFileSystem::Make(
+    const GcsOptions& options, const io::IOContext& io_context) {
   // Cannot use `std::make_shared<>` as the constructor is private.
-  return std::shared_ptr<GcsFileSystem>(new GcsFileSystem(options, context));
+  std::shared_ptr<GcsFileSystem> ptr(new GcsFileSystem(options, io_context));
+  return ptr;
 }
 
 GcsFileSystem::GcsFileSystem(const GcsOptions& options, const io::IOContext& context)

cpp/src/arrow/filesystem/gcsfs.h

@@ -231,8 +231,7 @@ class ARROW_EXPORT GcsFileSystem : public FileSystem {
       const std::shared_ptr<const KeyValueMetadata>& metadata) override;
 
   /// Create a GcsFileSystem instance from the given options.
-  // TODO(ARROW-16884): make this return Result for consistency
-  static std::shared_ptr<GcsFileSystem> Make(
+  static Result<std::shared_ptr<GcsFileSystem>> Make(
       const GcsOptions& options, const io::IOContext& = io::default_io_context());
 
  private: