allow isTruncated to be optional bool (#626)

Author: dayaffe

Sources/ClientRuntime/Pagination/PaginatorSequence.swift

@@ -12,13 +12,13 @@ public struct PaginatorSequence<OperationStackInput: PaginateToken, OperationSta
     let input: OperationStackInput
     let inputKey: KeyPath<OperationStackInput, OperationStackInput.Token?>?
     let outputKey: KeyPath<OperationStackOutput, OperationStackInput.Token?>
-    var isTruncatedKey: KeyPath<OperationStackOutput, Bool>?
+    var isTruncatedKey: KeyPath<OperationStackOutput, Bool?>?
     let paginationFunction: (OperationStackInput) async throws -> OperationStackOutput
 
     public init(input: OperationStackInput,
                 inputKey: KeyPath<OperationStackInput, OperationStackInput.Token?>? = nil,
                 outputKey: KeyPath<OperationStackOutput, OperationStackInput.Token?>,
-                isTruncatedKey: KeyPath<OperationStackOutput, Bool>? = nil,
+                isTruncatedKey: KeyPath<OperationStackOutput, Bool?>? = nil,
                 paginationFunction: @escaping (OperationStackInput) async throws -> OperationStackOutput) {
         self.input = input
         self.inputKey = inputKey
@@ -51,7 +51,7 @@ public struct PaginatorSequence<OperationStackInput: PaginateToken, OperationSta
 
                 // Use isTruncatedKey from the sequence to check if pagination should continue
                 if let isTruncatedKey = sequence.isTruncatedKey {
-                    let isTruncated = output[keyPath: isTruncatedKey]
+                    let isTruncated = output[keyPath: isTruncatedKey] ?? false
                     if !isTruncated {
                         // set token to nil to break out of the next iteration
                         token = nil