[FIX] Blockstack errors in IE 11 (#12338)

Closes #12226
This pull request removes `blockstack` dependency from the browser's modules bundle using [dynamic-import](https://docs.meteor.com/packages/dynamic-import.html).

.circleci/config.yml

@@ -80,6 +80,8 @@ jobs:
 
       - run:
           name: Build Rocket.Chat
+          environment:
+            TOOL_NODE_FLAGS: --max_old_space_size=4096
           command: |
             if [[ $CIRCLE_TAG ]]; then meteor reset; fi
             set +e

packages/rocketchat-blockstack/client/main.js

@@ -2,9 +2,7 @@ import { Meteor } from 'meteor/meteor';
 import { ServiceConfiguration } from 'meteor/service-configuration';
 import { check, Match } from 'meteor/check';
 import { Session } from 'meteor/session';
-
 import './routes';
-import { redirectToSignIn, signUserOut } from 'blockstack';
 
 const handleError = (error) => error && Session.set('errorMessage', error.reason || 'Unknown error');
 
@@ -29,7 +27,8 @@ Meteor.loginWithBlockstack = (options, callback = handleError) => {
 			manifestURI: String,
 		}));
 
-		return redirectToSignIn(options.redirectURI, options.manifestURI, options.scopes);
+		import('blockstack/dist/blockstack').then(({ redirectToSignIn }) =>
+			redirectToSignIn(options.redirectURI, options.manifestURI, options.scopes));
 	} catch (err) {
 		callback.call(Meteor, err);
 	}
@@ -45,7 +44,8 @@ Meteor.logout = (...args) => {
 
 	if (serviceConfig && blockstackAuth) {
 		Session.delete('blockstack_auth');
-		signUserOut(window.location.href);
+		import('blockstack/dist/blockstack').then(({ signUserOut }) =>
+			signUserOut(window.location.href));
 	}
 
 	return meteorLogout(...args);

packages/rocketchat-blockstack/client/routes.js

@@ -1,7 +1,6 @@
 import { Meteor } from 'meteor/meteor';
 import { Accounts } from 'meteor/accounts-base';
 import { FlowRouter } from 'meteor/kadira:flow-router';
-import blockstack from 'blockstack';
 
 const blockstackLogin = (authResponse, userData = {}) => {
 	Accounts.callLoginMethod({
@@ -19,6 +18,8 @@ const blockstackLogin = (authResponse, userData = {}) => {
 FlowRouter.route('/_blockstack/validate', {
 	name: 'blockstackValidate',
 	async action(params, queryParams) {
+		const blockstack = await import('blockstack/dist/blockstack');
+
 		if (Meteor.userId()) {
 			console.log('Blockstack Auth requested when already logged in. Reloading.');
 			return FlowRouter.go('home');