Fix tablet layout for in-app messaging (#2032)

* Rename fine-tuning methods to reflect size class rather than orientation

* Modify existing constraints to de-portrait tablet layout, need a card width for tablet now

* Further constraint tinkering, add identifiers for better auto layout debugging

* More constraints for "landscape" appearance in tablet. Looks good for every case except Thin Image, which blows up the height of the message card

* Fix fine tune layout methods to correctly fine tune for compact height and width

* Update layout constraint identifiers to match titles in document outline for easier debugging

* Revert superfluous method name changes for layout fine tuning methods

Author: christibbs

Firebase/InAppMessagingDisplay/Modal/FIDModalViewController.m

@@ -405,14 +405,15 @@ - (void)layoutFineTuneInLandscapeMode {
 - (void)viewDidLayoutSubviews {
   [super viewDidLayoutSubviews];
 
-  if (self.buttonBottomToContainerBottomInPortraitMode.active) {
-    FIRLogDebug(kFIRLoggerInAppMessagingDisplay, @"I-FID300009",
-                @"Modal view rendered in portrait mode");
-    [self layoutFineTuneInPortraitMode];
-  } else {
+  if (self.traitCollection.horizontalSizeClass == UIUserInterfaceSizeClassRegular ||
+      self.traitCollection.verticalSizeClass == UIUserInterfaceSizeClassCompact) {
     FIRLogDebug(kFIRLoggerInAppMessagingDisplay, @"I-FID300010",
                 @"Modal view rendered in landscape mode");
     [self layoutFineTuneInLandscapeMode];
+  } else {
+    FIRLogDebug(kFIRLoggerInAppMessagingDisplay, @"I-FID300009",
+                @"Modal view rendered in portrait mode");
+    [self layoutFineTuneInPortraitMode];
   }
 
   // always scroll to the top in case the body area is scrollable