Report touch input status in rageshakes, analytics

This reports whether the device has touch input as a primary input mechanism in
rageshakes and analytics.

For analytics, this replaces the identity server (which ends up being reported
as "<redacted>" by default anyway) because Matomo only supports a limited number
of custom variables.

src/rageshake/submit-rageshake.js

@@ -73,6 +73,12 @@ export default async function sendBugReport(bugReportEndpoint, opts) {
         installedPWA = window.matchMedia('(display-mode: standalone)').matches;
     } catch (e) { }
 
+    let touchInput = "UNKNOWN";
+    try {
+        // MDN claims broad support across browsers
+        touchInput = window.matchMedia('(pointer: coarse)').matches;
+    } catch (e) { }
+
     const client = MatrixClientPeg.get();
 
     console.log("Sending bug report.");
@@ -83,6 +89,7 @@ export default async function sendBugReport(bugReportEndpoint, opts) {
     body.append('version', version);
     body.append('user_agent', userAgent);
     body.append('installed_pwa', installedPWA);
+    body.append('touch_input', touchInput);
 
     if (client) {
         body.append('user_id', client.credentials.userId);