feat(dialog): Add a chaining class that suppresses scrim animations.

PiperOrigin-RevId: 616132734

packages/mdc-dialog/_mixins.scss

@@ -395,7 +395,8 @@
 
     .mdc-dialog__container {
       @include feature-targeting.targets($feat-animation) {
-        transition: opacity 75ms linear,
+        transition:
+          opacity 75ms linear,
           animation-functions.enter(transform, 150ms);
       }
     }
@@ -423,6 +424,16 @@
     }
   }
 
+  // Override the above transitions when chaining dialogs.
+  .mdc-dialog--chaining .mdc-dialog__scrim {
+    @include feature-targeting.targets($feat-animation) {
+      transition: none;
+    }
+    @include feature-targeting.targets($feat-structure) {
+      opacity: 1;
+    }
+  }
+
   .mdc-dialog--open {
     .mdc-dialog__scrim {
       @include feature-targeting.targets($feat-structure) {