Also make sure that email is still nil when updating email with userId.

Author: tapashmajumder

Tests/swift-sdk-swift-tests/IterableAPITests.swift

@@ -206,6 +206,7 @@ class IterableAPITests: XCTestCase {
                                     TestUtils.validateElementPresent(withName: AnyHashable.ITBL_KEY_NEW_EMAIL, andValue: newEmail, inDictionary: body)
                                     TestUtils.validateElementPresent(withName: AnyHashable.ITBL_KEY_CURRENT_USER_ID, andValue: currentUserId, inDictionary: body)
                                     XCTAssertEqual(IterableAPI.userId, currentUserId)
+                                    XCTAssertNil(IterableAPI.email)
                                     expectation.fulfill()
         },
                                 onFailure: {(reason, _) in