fix: Swift UserId and DeviceId setter

Sources/Amplitude/Amplitude.h

@@ -541,15 +541,18 @@ typedef NSDictionary *_Nullable (^AMPLocationInfoBlock)(void);
  */
 
 /**
- Sets the userId.
+ Sets the userId and starts a new session.
+
+ **Note: this is deprecated** - please use `setUserId:(NSString*) userId startNewSession:(BOOL)startNewSession`
+
  @param userId If your app has its own login system that you want to track users with, you can set the userId.
  @see [Setting Custom UserIds](https://github.com/amplitude/Amplitude-iOS#setting-custom-user-ids)
  */
 
 - (void)setUserId:(nullable NSString *)userId;
 
 /**
- Sets the userId and starts a new session. The previous session for the previous user will be terminated and a new session will begin for the new user id.
+ Sets the userId. If startNewSession is true, the previous session for the previous user will be terminated and a new session will begin for the new userId.
 
  @param userId If your app has its own login system that you want to track users with, you can set the userId.
 

Sources/Amplitude/Amplitude.m

@@ -87,6 +87,8 @@ @interface Amplitude()
 @property (nonatomic, assign) long long sessionId;
 @property (nonatomic, assign) BOOL backoffUpload;
 @property (nonatomic, assign) int backoffUploadBatchSize;
+@property (nonatomic, copy, readwrite, nullable) NSString *userId;
+@property (nonatomic, copy, readwrite) NSString *deviceId;
 #if TARGET_OS_IOS || TARGET_OS_MACCATALYST
 @property (nonatomic, strong) AMPEventExplorer *eventExplorer;
 #endif

Sources/Amplitude/AmplitudePrivate.h

@@ -11,8 +11,6 @@
 @interface Amplitude ()
 
 @property (nonatomic, copy, readwrite) NSString *apiKey;
-@property (nonatomic, copy, readwrite) NSString *userId;
-@property (nonatomic, copy, readwrite) NSString *deviceId;
 @property (nonatomic, copy, readwrite) NSString *instanceName;
 
 @end