[IMP] web_editor: align m2m widget label with first element

The m2m widget label is aligned at the middle of the height of the whole
option's display.

This commit makes the m2m widget label aligned with the first element
(either the first active value, or the "Choose a record..." dropdown if
no value is selected).

task-2811746

closes odoo/odoo#108227

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/web_editor/static/src/scss/wysiwyg_snippets.scss

@@ -1409,13 +1409,16 @@ body.editor_enable.editor_has_snippets {
                 width: 100%;
                 max-height: 200px;
                 overflow-y: auto;
-                margin-bottom: $o-we-sidebar-content-field-spacing / 2;
 
                 table {
                     @include o-input-number-no-arrows();
                     table-layout: auto;
                     width: 100%;
+                    margin-bottom: $o-we-sidebar-content-field-spacing / 2;
 
+                    &:empty {
+                        margin-bottom: 0;
+                    }
                     input {
                         width: 100%;
                         border: $o-we-sidebar-content-field-border-width solid $o-we-sidebar-content-field-border-color;
@@ -1515,6 +1518,9 @@ body.editor_enable.editor_has_snippets {
                 margin-top: 0;
                 max-width: 100%;
             }
+            we-title {
+                align-self: flex-start;
+            }
         }
 
         //----------------------------------------------------------------------