fix(material/autocomplete): resets autocomplete panel positionStrategy when not in mobile landscape

Updates the previous fix which checks for Breakpoint.HandsetLandscape and applies flexibleDimensions
withGrowAfterOpen and adds withViewportMargin and removes those values if Breakpoint.HandsetLandscape
is false.

Fixes b/284148377

Author: essjay05

src/material/autocomplete/autocomplete-trigger.ts

@@ -809,7 +809,10 @@ export class MatAutocompleteTrigger
               .withGrowAfterOpen(true)
               .withViewportMargin(8);
           } else {
-            this._positionStrategy.withGrowAfterOpen(false);
+            this._positionStrategy
+              .withFlexibleDimensions(false)
+              .withGrowAfterOpen(false)
+              .withViewportMargin(0);
           }
         });
     } else {