fix(material/snack-bar): add max height for snack bar (angular#32000)

Adds a max height for the snack bar in case users pass huge strings into it.

Fixes angular#31996.

Author: crisbeto

src/material/snack-bar/simple-snack-bar.scss

@@ -2,4 +2,9 @@
 // wrapping layer to the mdc-snackbar__surface, it should also include flex display.
 .mat-mdc-simple-snack-bar {
   display: flex;
+
+  .mat-mdc-snack-bar-label {
+    max-height: 50vh;
+    overflow: auto;
+  }
 }