Revert "Revert code style for checking if the label should be hidden to how it was before."

The previous change wasn't actually cosmetic. If ticklabelindex is set, the skipLabel flag should not be tested here.

This reverts commit 5861fc5.

Author: my-tien

src/plots/cartesian/axes.js

@@ -1303,9 +1303,14 @@ axes.calcTicks = function calcTicks(ax, opts) {
         } else {
             lastVisibleHead = ax._prevDateHead;
             t = setTickLabel(ax, tickVals[i]);
-            if (tickVals[i].skipLabel
-                || (ticklabelIndex && allTicklabelVals.indexOf(tickVals[i]) === -1)) {
-                hideLabel(t);
+            if (ticklabelIndex) {
+                if (allTicklabelVals.indexOf(tickVals[i]) === -1) {
+                    hideLabel(t);
+                }
+            } else {
+                if (tickVals[i].skipLabel) {
+                    hideLabel(t);
+                }
             }
 
             ticksOut.push(t);