fix: Advanced editor styles [FC-0076] (#36221)

* Adds padding to the text of the competition block editor.
* Fix the style of the Save and Cancel buttons of the PDF block editor.
* Moves the Save and Cancel buttons to the bottom of the modal.
* Moves the Save and Cancel button to the right.
* Which edX user roles will this change impact? "Course Author"

cms/static/sass/course-unit-mfe-iframe-bundle.scss

@@ -316,6 +316,7 @@ body {
 
       .openassessment_save_button,
       .save-button,
+      .action-save,
       .continue-button {
         color: $white;
         background-color: $primary;
@@ -347,6 +348,7 @@ body {
       }
 
       .openassessment_cancel_button,
+      .action-cancel,
       .cancel-button {
         color: $text-color;
         background-color: $transparent;
@@ -384,6 +386,8 @@ body {
 
   // Additions for the xblock editor on the Library Authoring
   &.xblock-iframe-content {
+    height: 100%;
+
     // Reset the max-height to allow the settings list to grow
     .wrapper-comp-settings .list-input.settings-list {
       max-height: unset;
@@ -411,6 +415,31 @@ body {
         }
       }
     }
+
+    .xblock-v1-studio_view {
+      height: 100%;
+
+      .editor-with-buttons {
+        display: flex;
+        flex-direction: column;
+        justify-content: space-between;
+        height: 100%;
+
+        .list-input {
+          height: 90vh;
+        }
+      }
+
+      &.xmodule_DoneXBlock {
+        margin-top: 60px;
+        padding: 0 20px;
+      }
+
+      .xblock-actions {
+        display: flex;
+        justify-content: flex-end;
+      }
+    }
   }
 }