[IMP] web_editor, portal: review img/fa display rules mixup

Part of https://github.com/odoo/odoo/pull/53930
task-2157252

addons/portal/static/src/scss/portal.scss

@@ -208,11 +208,6 @@ img, .media_iframe_video, .o_image {
         margin-right: $grid-gutter-width / 2;
     }
 }
-img.o_we_custom_image {
-    // Images added with the editor are .img-fluid by default but should
-    // still behave like inline content.
-    display: inline-block;
-}
 
 // Others
 ::-moz-selection {

addons/web_editor/static/src/scss/web_editor.common.scss

@@ -149,8 +149,13 @@ ol > li.o_indent, ul > li.o_indent {
     }
 }
 
-
 // Medias
+img.o_we_custom_image {
+    // Images added with the editor are .img-fluid by default but should
+    // still behave like inline content.
+    display: inline-block;
+}
+
 img.shadow {
     box-shadow: 0px 3px 8px rgba(0, 0, 0, 0.2);
 }
@@ -185,7 +190,8 @@ img.ml-auto, img.mx-auto {
 .fa-10x {
     font-size: 10em;
 }
-.fa.d-block.mx-auto {
+.fa.mx-auto {
+    display: block;
     text-align: center;
 }
 
@@ -236,8 +242,6 @@ html[data-browser^="msie"] div.media_iframe_video iframe {
     margin-left: 0;
 }
 
-
-
 // Fields
 address {
     .fa.fa-mobile-phone {

addons/web_editor/static/src/scss/wysiwyg.scss

@@ -382,11 +382,6 @@ img::selection {
     background: transparent;
 }
 
-.fa.mx-auto,
-img.o_we_custom_image.mx-auto {
-    display: block;
-}
-
 @include media-breakpoint-down(md) {
     #web_editor-top-edit {
         position: initial !important;