Revert buffering single selection

We solved the "sliver" problem by buffering the selected boundary.

Although it "looks nicer" to have the buffer be consistent when toggling
between 1 and 2 selected neighbourhoods, buffering affects the
aggregated prioritization metrics.

But when you have only one neighbourhood selected, the "aggregated"
metrics should match that of the one boundary on the map **exactly**.

Having the visual buffer jitter a little between 1 and 2 selections is
the lesser evil.

Author: michaelkirk

web/src/AutoBoundariesMode.svelte

@@ -64,11 +64,11 @@
     if (newBoundaries.size === 0) {
       selectedBoundary = null;
       selectedBoundaries = newBoundaries;
+    } else if (newBoundaries.size === 1) {
+      selectedBoundary = newBoundaries.values().next().value!;
+      selectedBoundaries = newBoundaries;
     } else {
       // Aggregate the selected boundaries
-      // Note: We "aggregate" even when there's only one selected boundary
-      // because the output is slightly buffered, and we don't want that to jitter
-      // when toggling between 1 and 2 selected boundaries.
       let featureCollection = {
         type: "FeatureCollection" as const,
         features: Array.from(newBoundaries.values()),