test(toolbar): update testToolbarHasAllButtons count to 13 (Follow toggle) (#144)

FastSenseToolbar gained a Follow uitoggletool in #136 (commit 9f46c92,
between Live and Metadata), bringing the count from 12 to 13. The
TestToolbar assertion + comment hadn't been updated, leaving CI red on
the Q-Z batch.

Author: HanSur94

tests/suite/TestToolbar.m

@@ -37,8 +37,8 @@ function testToolbarHasAllButtons(testCase)
             children = get(tb.hToolbar, 'Children');
             % Buttons created in createToolbar(): cursor, crosshair, grid,
             % legend, autoscale, exportPNG, exportData, refresh, live,
-            % metadata, violations, theme = 12.
-            testCase.verifyEqual(numel(children), 12, ...
+            % follow, metadata, violations, theme = 13.
+            testCase.verifyEqual(numel(children), 13, ...
                 sprintf('testToolbarHasAllButtons: got %d', numel(children)));
         end