Compare a11y baseline by violation id only, not by node count

Node counts drift between local Electron-on-macOS and CI headless-Chromium-on-Linux
for the same underlying violations, so the count was failing CI on
diffs that aren't really diffs. id-only is the conventional baseline shape anyway.

Author: trevor-scheer

packages/graphiql/cypress/e2e/a11y.cy.ts

@@ -46,11 +46,12 @@ function checkOrCapture(checkpoint: string) {
       } else {
         const baselineEntries: ViolationSummary[] =
           (baseline as Baseline)[checkpoint] ?? [];
-        const baselineKeys = new Set(
-          baselineEntries.map(v => `${v.id}:${v.nodeCount}`),
-        );
+        // Compare by violation id only — node counts drift between local
+        // (Electron on macOS) and CI (headless Chromium on Linux) for the
+        // same underlying issues, so they're not a reliable key.
+        const baselineKeys = new Set(baselineEntries.map(v => v.id));
         const newViolations = violations.filter(
-          v => !baselineKeys.has(`${v.id}:${v.nodes.length}`),
+          v => !baselineKeys.has(v.id),
         );
         if (newViolations.length > 0) {
           const summary = newViolations