MC-878: Button stretches outside parent when button has a lot of text

- Added word wrapping for firefox

Author: Hwashiang Yu

app/code/Magento/PageBuilder/view/adminhtml/web/css/source/content-type/button-item/_default.less

@@ -29,6 +29,7 @@
         a[data-element='link'] {
             max-width: 100%;
             transition: min-width .5s ease;
+            word-wrap: break-word;
             [data-element='link_text'] {
                 max-width: 100%;
             }