Fix horizontal scrolling on pages including Streamfield ImageText blo…

…ck (#12444)

* Fix horizontal scroll on specific blocs by calculating a pixel less than bs vs tw resolves.

* Moved fix code to bottom of file and added descriptive comment.

* Update `image_text` block to fix extra pixel in margin for `tw-row` classes.

* Specify the viewport in which the fix is applied in order to avoid modifying medium and large screens current margins.

network-api/networkapi/wagtailpages/templates/wagtailpages/blocks/image_text.html

@@ -2,7 +2,7 @@
 {% load l10n wagtailcore_tags wagtailimages_tags %}
 
 {% block block_content %}
-    <div class="tw-row tw-my-8">
+    <div class="tw-row tw-my-8 !tw-mr-[calc(-1rem+1px)] small:!tw-mr-[-1rem]">
         {% if value.small %}
             <div class="tw-w-full tw-px-8 tw-flex tw-flex-nowrap">
                 <div class="tw-mr-6 tw-shrink-0 tw-w-24">