Merge branch 'feature/LoadingOverlay-Text' into 'develop'

Option to show text in the loading overlay screen

### Summary
Adding option to show text on loading overlay screen. 

### JIRA Ticket
[ONEAPP-5807](https://onejira.verizon.com/browse/ONEAPP-5807)

Co-authored-by: Sumanth Nadigadda <sumanth.nadigadda@verizon.com>

See merge request https://gitlab.verizon.com/BPHV_MIPS/mvm_core/-/merge_requests/286

MVMCore/MVMCore/LoadHandling/LoadingOverlay/MVMCoreLoadingOverlayHandler.h

@@ -17,6 +17,9 @@
 // Starts Loading. Every start loading call must be terminated with an end loading call.
 - (void)startLoading;
 
+// Starts Loading, by showing the text in the center
+- (void)startLoadingWith:(nullable NSAttributedString *) text;
+
 // Returns if it is showing.
 - (BOOL)isShowing;
 

MVMCore/MVMCore/LoadHandling/LoadingOverlay/MVMCoreLoadingOverlayHandler.m

@@ -52,6 +52,10 @@
 #pragma mark - Overlay Functions
 
 - (void)startLoading {
+    [self startLoadingWith:nil];
+}
+
+- (void)startLoadingWith:(nullable NSAttributedString *)text {
     
     [MVMCoreDispatchUtility performBlockOnMainThread:^{
         
@@ -73,7 +77,7 @@
                 }
                 
                 // Restarts the loading animation.
-                [self.loadingViewController startLoading];
+                [self.loadingViewController startLoadingWith:text];
                 
                 if (self.animatingOut) {
                     

MVMCore/MVMCore/LoadHandling/LoadingOverlay/MVMCoreLoadingViewControllerProtocol.h

@@ -14,4 +14,8 @@
 // Called when the view controller should stop animating loading.
 - (void)stopLoading;
 
+@optional
+// Called when the view controller should animate loading with custom text
+- (void)startLoadingWith:(nullable NSAttributedString *) text;
+
 @end