Start using in-process WebRTC plotter

Now that we can link things a bit more sanely, we may as well start
using it and gradually remove dependencies on matplotlibcpp.

Change-Id: I344df7ca0dd70d615d5d63f9a3c9217d73dbd7de
diff --git a/frc971/analysis/plot_data_utils.ts b/frc971/analysis/plot_data_utils.ts
index e918379..def34ed 100644
--- a/frc971/analysis/plot_data_utils.ts
+++ b/frc971/analysis/plot_data_utils.ts
@@ -64,7 +64,7 @@
             plot.getAxisLabels().setXLabel(figure.xlabel());
           }
           if (figure.ylabel()) {
-            plot.getAxisLabels().setYLabel(figure.xlabel());
+            plot.getAxisLabels().setYLabel(figure.ylabel());
           }
           if (figure.shareXAxis()) {
             for (const other of linkedXAxes) {