Add GridDimensionSpecs to fixed landscape and make grid dimension generalized so we can use it to determine row count or col count

Bug: 364711064
Flag: com.android.launcher3.one_grid_specs
Test: HomeScreenImageTest
Change-Id: If1dafedc710ebc483fc7b6b5cd6cae6f70dc3cfc
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 8981024..aaa0c41 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -789,7 +789,7 @@
             LauncherPrefs.get(this).put(LauncherPrefs.ALLOW_ROTATION, false);
         }
         getRotationHelper().setFixedLandscape(
-                Objects.requireNonNull(mDeviceProfile.inv).isFixedLandscapeMode
+                Objects.requireNonNull(mDeviceProfile.inv).isFixedLandscape
         );
     }