[Swift] Implements FlatbuffersVector which confirms to RandomAccessCollection (#8752)

* Implements FlatbuffersVector in swift

Implements FlatbuffersVector which confirms to RandomAccessCollection,
this would give us semi-native sugary syntax to all the arrays in swift port.

This work will also be the foundation of using arrays in swift

* Fix failing tests for Swift

benchmarks/swift/Package.swift

@@ -20,7 +20,7 @@ import PackageDescription
 let package = Package(
   name: "benchmarks",
   platforms: [
-    .macOS(.v13)
+    .macOS(.v13),
   ],
   dependencies: [
     .package(path: "../.."),
@@ -37,6 +37,6 @@ let package = Package(
       ],
       path: "Benchmarks/FlatbuffersBenchmarks",
       plugins: [
-        .plugin(name: "BenchmarkPlugin", package: "package-benchmark")
-      ])
+        .plugin(name: "BenchmarkPlugin", package: "package-benchmark"),
+      ]),
   ])