legacy iOS dialog provider: fix compilation warnings

(cherry picked from commit 44d520e12d96b675c5e8b6e2115e990c9f63ed20)

Sources/VLCCustomDialogProvider.m

@@ -251,7 +251,7 @@ static void updateProgressCallback(void *p_data,
     if ([self.customRenderer respondsToSelector:@selector(showProgressWithTitle:message:isIndeterminate:position:cancelString:withReference:)]) {
         [self.customRenderer showProgressWithTitle:dialogData[1]
                                            message:dialogData[2]
-                                   isIndeterminate:dialogData[3]
+                                   isIndeterminate:[dialogData[3] boolValue]
                                           position:[dialogData[4] floatValue]
                                       cancelString:[dialogData[5] isEqualToString:@""] ? NULL : dialogData[5]
                                      withReference:dialogData[0]];

Sources/VLCiOSLegacyDialogProvider.m

@@ -31,6 +31,14 @@
 {
     VLCLibrary *_libraryInstance;
 }
+
+- (instancetype)initWithLibrary:(VLCLibrary *)library;
+- (void)displayError:(NSArray * _Nonnull)dialogData;
+- (void)displayLoginDialog:(NSArray * _Nonnull)dialogData;
+- (void)displayQuestion:(NSArray * _Nonnull)dialogData;
+- (void)displayProgressDialog:(NSArray * _Nonnull)dialogData;
+- (void)updateDisplayedProgressDialog:(NSArray * _Nonnull)dialogData;
+
 @end
 
 @interface VLCBlockingAlertView : UIAlertView <UIAlertViewDelegate>