[FIX] web: correctly target 'o_dropdown_item' child

Partially revert 47acba560a removing rules defining '<a>' children as
exceptions. Having an element (either <a> or a <span>) wrapping the
entry content is indeed now considered the norm.

This commit will extend bootstrap 'dropdown-item' design to any
'o_dropdown_item' first-child rather than on element itself.

task-2579123

addons/web/static/src/core/dropdown/dropdown.scss

@@ -25,23 +25,6 @@
   &.selected { // Legacy
     @extend .dropdown-item.active;
   }
-
-}
-
-.dropdown-menu .dropdown-item {
-  // Using <a> tags inside a '.dropdown-item' elements  should not be necessary
-  // since the class in usually applied to the <a> tag itself.
-  // The following rules will handle custom layouts needs (eg '.o_user_menu').
-  &:not(.disabled):not(:disabled) a:not(.disabled):not(:disabled) {
-    @include o-hover-text-color($dropdown-link-color, $dropdown-link-hover-color);
-    font-weight: inherit;
-  }
-
-  &.disabled a, &:disabled a {
-    @include o-hover-text-color(
-      $dropdown-link-disabled-color,
-      $dropdown-link-disabled-color);
-  }
 }
 
 .dropdown-header {
@@ -78,21 +61,17 @@
     &.o_dropdown_menu_right {
       @extend .dropdown-menu-right;
     }
-  }
 
-  &_item {
-    @extend .dropdown-item;
-
-    // we want the dropdownitem first child to define its own padding
-    // because it can be an <a href/>
-    padding: 0;
-    > *:first-child {
-      padding: $dropdown-item-padding-y $dropdown-item-padding-x;
-      display: flex;
-    }
-
-    &.o_dropdown_active {
-      @extend .dropdown-item:hover;
+    // Since wrapping entry's content is the norm, @extend bootstrap
+    // '.dropdown-item' classes to the inner element (eg. <a> or <span>)
+    // rather that on 'o_dropdown_item'.
+    .o_dropdown_item {
+      > :first-child {
+        @extend .dropdown-item;
+      }
+      &.selected > :first-child {
+        @extend .active;
+      }
     }
   }
 

addons/web/static/src/legacy/scss/navbar.scss

@@ -105,7 +105,7 @@
     @include border-top-radius(0);
   }
 
-  .o_dropdown_menu_group_entry {
+  .o_dropdown_menu_group_entry.o_dropdown_item {
     > *:first-child {
       padding-left: $o-dropdown-hpadding * 1.5;
     }