[SPARK-54045] Upgrade FlatBuffers to v25.9.23

### What changes were proposed in this pull request?

This PR aims to upgrade `FlatBuffers` to `v25.9.23`

### Why are the changes needed?

To bring the latest bug fixes and improvements like `Windows` support.
- https://github.com/google/flatbuffers/releases/tag/v25.9.23 (2025-09-23)
  - google/flatbuffers#8484
  - google/flatbuffers#8577
  - google/flatbuffers#8622
  - google/flatbuffers#8637
  - google/flatbuffers#8643
  - google/flatbuffers#8650
  - google/flatbuffers#8649
  - google/flatbuffers#8702

### Does this PR introduce _any_ user-facing change?

No. There is no behavior change.

### How was this patch tested?

Pass the CIs.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #254 from dongjoon-hyun/SPARK-54045.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

Package.swift

@@ -37,7 +37,7 @@ let package = Package(
     .package(url: "https://github.com/grpc/grpc-swift-2.git", exact: "2.1.0"),
     .package(url: "https://github.com/grpc/grpc-swift-protobuf.git", exact: "2.1.1"),
     .package(url: "https://github.com/grpc/grpc-swift-nio-transport.git", exact: "2.2.0"),
-    .package(url: "https://github.com/google/flatbuffers.git", branch: "v25.2.10"),
+    .package(url: "https://github.com/google/flatbuffers.git", branch: "v25.9.23"),
   ],
   targets: [
     .target(

README.md

@@ -21,7 +21,7 @@ So far, this library project is tracking the upstream changes of [Apache Arrow](
 - [gRPC Swift 2.1 (July 2025)](https://github.com/grpc/grpc-swift-2/releases/tag/2.1.0)
 - [gRPC Swift Protobuf 2.1 (August 2025)](https://github.com/grpc/grpc-swift-protobuf/releases/tag/2.1.1)
 - [gRPC Swift NIO Transport 2.2 (September 2025)](https://github.com/grpc/grpc-swift-nio-transport/releases/tag/2.2.0)
-- [FlatBuffers v25.2.10 (February 2025)](https://github.com/google/flatbuffers/releases/tag/v25.2.10)
+- [FlatBuffers v25.9.23 (September 2025)](https://github.com/google/flatbuffers/releases/tag/v25.9.23)
 - [Apache Arrow Swift](https://github.com/apache/arrow-swift)
 
 ## How to use in your apps

Sources/SparkConnect/ArrowReader.swift

@@ -268,9 +268,7 @@ public class ArrowReader {  // swiftlint:disable:this type_body_length
 
       offset += Int(MemoryLayout<UInt32>.size)
       streamData = input[offset...]
-      let dataBuffer = ByteBuffer(
-        data: streamData,
-        allowReadingUnalignedBuffers: true)
+      let dataBuffer = ByteBuffer(data: streamData)
       let message = org_apache_arrow_flatbuf_Message.getRootAsMessage(bb: dataBuffer)
       switch message.headerType {
       case .recordbatch:
@@ -324,9 +322,7 @@ public class ArrowReader {  // swiftlint:disable:this type_body_length
     let result = ArrowReaderResult()
     let footerStartOffset = fileData.count - Int(footerLength + 4)
     let footerData = fileData[footerStartOffset...]
-    let footerBuffer = ByteBuffer(
-      data: footerData,
-      allowReadingUnalignedBuffers: useUnalignedBuffers)
+    let footerBuffer = ByteBuffer(data: footerData)
     let footer = org_apache_arrow_flatbuf_Footer.getRootAsFooter(bb: footerBuffer)
     let schemaResult = loadSchema(footer.schema!)
     switch schemaResult {
@@ -356,9 +352,7 @@ public class ArrowReader {  // swiftlint:disable:this type_body_length
         recordBatch.offset + (Int64(MemoryLayout<Int32>.size) * messageOffset)
       let messageEndOffset = messageStartOffset + Int64(messageLength)
       let recordBatchData = fileData[messageStartOffset..<messageEndOffset]
-      let mbb = ByteBuffer(
-        data: recordBatchData,
-        allowReadingUnalignedBuffers: useUnalignedBuffers)
+      let mbb = ByteBuffer(data: recordBatchData)
       let message = org_apache_arrow_flatbuf_Message.getRootAsMessage(bb: mbb)
       switch message.headerType {
       case .recordbatch:
@@ -410,9 +404,7 @@ public class ArrowReader {  // swiftlint:disable:this type_body_length
     result: ArrowReaderResult,
     useUnalignedBuffers: Bool = false
   ) -> Result<Void, ArrowError> {
-    let mbb = ByteBuffer(
-      data: dataHeader,
-      allowReadingUnalignedBuffers: useUnalignedBuffers)
+    let mbb = ByteBuffer(data: dataHeader)
     let message = org_apache_arrow_flatbuf_Message.getRootAsMessage(bb: mbb)
     switch message.headerType {
     case .schema:

Sources/SparkConnect/Message_generated.swift

@@ -20,6 +20,7 @@
 // swiftformat:disable all
 
 import FlatBuffers
+import Common
 
 /// @nodoc
 public enum org_apache_arrow_flatbuf_CompressionType: Int8, Enum, Verifiable {

Sources/SparkConnect/Schema_generated.swift

@@ -20,6 +20,7 @@
 // swiftformat:disable all
 
 import FlatBuffers
+import Common
 
 /// @nodoc
 public enum org_apache_arrow_flatbuf_MetadataVersion: Int16, Enum, Verifiable {

Sources/SparkConnect/SparseTensor_generated.swift

@@ -20,6 +20,7 @@
 // swiftformat:disable all
 
 import FlatBuffers
+import Common
 
 /// @nodoc
 public enum org_apache_arrow_flatbuf_SparseMatrixCompressedAxis: Int16, Enum, Verifiable {