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/static/js/backform.pgadmin.js

@@ -2806,6 +2806,9 @@ define([
         options: {
           format: 'YYYY-MM-DD HH:mm:ss Z',
           icons: {
+            time: 'fa fa-clock',
+            data: 'fa fa-calendar-alt',
+            today: 'fa fa-calendar-check',
             clear: 'fa fa-trash',
           },
           buttons: {

web/pgadmin/static/js/backgrid.pgadmin.js

@@ -1780,6 +1780,9 @@ define([
         options = _.extend({
           format: 'YYYY-MM-DD HH:mm:ss Z',
           icons: {
+            time: 'fa fa-clock',
+            data: 'fa fa-calendar-alt',
+            today: 'fa fa-calendar-check',
             clear: 'fa fa-trash',
           },
           buttons: {

web/pgadmin/static/scss/_alertify.overrides.scss

@@ -200,7 +200,6 @@
 
 .pg-alertify-icon-button {
   &:before {
-    font-size: 1.1em !important;
     line-height: 1.2;
     font-family: $font-family-icon;
     font-weight: 900;

web/pgadmin/static/scss/_webcabin.pgadmin.scss

@@ -34,6 +34,10 @@
   display: flex;
   border-radius: $btn-border-radius;
   margin: auto;
+
+  & .pg-font-icon {
+    line-height: unset;
+  }
 }
 
 /* darken % taken from bootstrap - button_variant */
@@ -167,7 +171,7 @@
   padding: 0rem 0.75rem;
 
   &.fa, &.pg-font-icon{
-    padding: 0rem 0.25rem 0rem 0rem
+    padding: 0rem 0.25rem 0rem 0rem;
   }
 }