fix(logging): Add more details to onerror and onunhandledrejection errors.

react/features/base/lib-jitsi-meet/middleware.js

 
         // eslint-disable-next-line max-params
         window.onerror = (message, source, lineno, colno, error) => {
-            JitsiMeetJS.getGlobalOnErrorHandler(
-                message, source, lineno, colno, error);
+            const errMsg = message || (error && error.message);
+            const stack = error && error.stack;
+
+            JitsiMeetJS.getGlobalOnErrorHandler(errMsg, source, lineno, colno, stack);
 
             if (oldOnErrorHandler) {
                 oldOnErrorHandler(message, source, lineno, colno, error);
         const oldOnUnhandledRejection = window.onunhandledrejection;
 
         window.onunhandledrejection = function(event) {
-            JitsiMeetJS.getGlobalOnErrorHandler(
-                null, null, null, null, event.reason);
+            let message = event.reason;
+            let stack = 'n/a';
+
+            if (event.reason instanceof Error) {
+                ({ message, stack } = event.reason);
+            }
+
+            JitsiMeetJS.getGlobalOnErrorHandler(message, null, null, null, stack);
 
             if (oldOnUnhandledRejection) {
                 oldOnUnhandledRejection(event);