1) Added special handling for the extension to resolve the dependency.

2) Added 'is_sys_obj' to the ignore list of Schema Diff.
3) Font awesome v5 fixes.

web/pgadmin/browser/static/js/collection.js

@@ -247,7 +247,7 @@ define([
           type: 'delete',
           tooltip: gettext('Delete/Drop'),
           extraClasses: ['btn-primary-icon m-1', 'delete_multiple'],
-          icon: 'fa fa-lg fa-trash-alt',
+          icon: 'fa fa-trash-alt',
           disabled:  (_.isFunction(that.canDrop)) ? !(that.canDrop.apply(self, [data, item])) : (!that.canDrop),
           register: function(btn) {
             btn.on('click',() => {

web/pgadmin/browser/static/js/node.js

@@ -1246,7 +1246,7 @@ define('pgadmin.browser.node', [
               type: 'help',
               tooltip: gettext('SQL help for this object type.'),
               extraClasses: ['btn-primary-icon', 'btn-primary-icon', 'm-1'],
-              icon: 'fa fa-lg fa-info',
+              icon: 'fa fa-info',
               disabled: (that.sqlAlterHelp == '' && that.sqlCreateHelp == '') ? true : false,
               register: function(btn) {
                 btn.on('click',() => {
@@ -1499,7 +1499,7 @@ define('pgadmin.browser.node', [
               type: 'help',
               tooltip: gettext('SQL help for this object type.'),
               extraClasses: ['btn-primary-icon', 'pull-left', 'mx-1'],
-              icon: 'fa fa-lg fa-info',
+              icon: 'fa fa-info',
               disabled: (that.sqlAlterHelp == '' && that.sqlCreateHelp == '') ? true : false,
               register: function(btn) {
                 btn.on('click',() => {
@@ -1511,7 +1511,7 @@ define('pgadmin.browser.node', [
               type: 'help',
               tooltip: gettext('Help for this dialog.'),
               extraClasses: ['btn-primary-icon', 'pull-left', 'mx-1'],
-              icon: 'fa fa-lg fa-question',
+              icon: 'fa fa-question',
               disabled: (that.dialogHelp == '') ? true : false,
               register: function(btn) {
                 btn.on('click',() => {

web/pgadmin/browser/static/js/toolbar.js

@@ -30,7 +30,7 @@ let _defaultToolBarButtons = [
   {
     label: gettext('View Data'),
     ariaLabel: gettext('View Data'),
-    btnClass: 'fa fa-table',
+    btnClass: 'pg-font-icon sql-icon-lg icon-view-data',
     text: '',
     toggled: false,
     toggleClass: '',