[SPARK-52070] Fix Swift 6.0 compilation error

### What changes were proposed in this pull request?
This PR aims to fix the build for Swift 6.0.

### Why are the changes needed?
Currently, the build on Swift 6.0 is broken due to a syntax error.
- https://swiftpackageindex.com/apache/spark-connect-swift/builds

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?
Pass the CIs.

### Was this patch authored or co-authored using generative AI tooling?
No.

Closes #127 from williamhyun/switft6.

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

Author: williamhyun

Sources/SparkConnect/DataFrame.swift

@@ -1285,7 +1285,7 @@ public actor DataFrame: Sendable {
     _ ids: [String],
     _ values: [String]?,
     _ variableColumnName: String,
-    _ valueColumnName: String,
+    _ valueColumnName: String
   ) -> DataFrame {
     let plan = SparkConnectClient.getUnpivot(self.plan.root, ids, values, variableColumnName, valueColumnName)
     return DataFrame(spark: self.spark, plan: plan)

Sources/SparkConnect/SparkConnectClient.swift

@@ -925,7 +925,7 @@ public actor SparkConnectClient {
     _ ids: [String],
     _ values: [String]?,
     _ variableColumnName: String,
-    _ valueColumnName: String,
+    _ valueColumnName: String
   ) -> Plan {
     var unpivot = Spark_Connect_Unpivot()
     unpivot.input = child
@@ -984,7 +984,7 @@ public actor SparkConnectClient {
   func executeStreamingQueryCommand(
     _ id: String,
     _ runID: String,
-    _ command: StreamingQueryCommand.OneOf_Command,
+    _ command: StreamingQueryCommand.OneOf_Command
   ) async throws -> [ExecutePlanResponse] {
     var queryID = Spark_Connect_StreamingQueryInstanceId()
     queryID.id = id

Sources/SparkConnect/StreamingQuery.swift

@@ -86,7 +86,7 @@ public actor StreamingQuery: Sendable {
     return StreamingQueryException(
       exceptionMessage: result.exceptionMessage,
       errorClass: result.errorClass,
-      stackTrace: result.stackTrace,
+      stackTrace: result.stackTrace
     )
   }
 
@@ -99,7 +99,7 @@ public actor StreamingQuery: Sendable {
       statusMessage: result.statusMessage,
       isDataAvailable: result.isDataAvailable,
       isTriggerActive: result.isTriggerActive,
-      isActive: result.isActive,
+      isActive: result.isActive
     )
   }