[FIX] web_widget_numeric_step: always display on touch screens; avoid layout jumping otherwise

Before this patch:
- On a tablet, buttons wouldn't display (big screen; can't hover).
- On a PC, fields would make layout jumps while hovering.

@moduon MT-4472

web_widget_numeric_step/static/src/numeric_step.esm.js

@@ -9,14 +9,6 @@ export class NumericStep extends FloatField {
     setup() {
         super.setup();
     }
-    _onFocusInput(ev) {
-        const $el = $(ev.target).parent().find(".widget_numeric_step_btn");
-        $el.removeClass("d-lg-none");
-    }
-    _onFocusOutInput(ev) {
-        const $el = $(ev.target).find(".widget_numeric_step_btn");
-        $el.addClass("d-lg-none");
-    }
     _onStepClick(ev) {
         const $el = $(ev.target).parent().parent().find("input");
         $el.focus();
@@ -65,7 +57,6 @@ export class NumericStep extends FloatField {
 NumericStep.template = "web_widget_numeric_step";
 NumericStep.props = {
     ...standardFieldProps,
-    name: {type: String, optional: true},
     inputType: {type: String, optional: true},
     step: {type: Number, optional: true},
     min: {type: Number, optional: true},

web_widget_numeric_step/static/src/numeric_step.scss

@@ -0,0 +1,14 @@
+// Copyright 2023 Moduon Team S.L.
+// License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html)
+
+.widget_numeric_step {
+    // Hide the buttons until the user hovers if possible
+    @media (hover: hover) {
+        .btn_numeric_step {
+            visibility: hidden;
+        }
+    }
+    &:hover .btn_numeric_step {
+        visibility: visible;
+    }
+}

web_widget_numeric_step/static/src/numeric_step.xml

@@ -6,12 +6,8 @@ License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 -->
 <template>
     <t t-name="web_widget_numeric_step" owl="1">
-        <div
-            class="d-flex widget_numeric_step"
-            t-on-mouseleave="_onFocusOutInput"
-            t-on-mouseenter="_onFocusInput"
-        >
-            <div class="input-group-prepend d-lg-none widget_numeric_step_btn">
+        <div class="d-flex widget_numeric_step">
+            <div class="input-group-prepend widget_numeric_step_btn">
                 <button
                     class="fa fa-minus btn btn-default btn_numeric_step"
                     aria-label="Minus"
@@ -33,7 +29,7 @@ License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
                 t-on-keydown="_onKeyDown"
                 t-on-wheel="_onWheel"
             />
-            <div class="input-group-append d-lg-none widget_numeric_step_btn">
+            <div class="input-group-append widget_numeric_step_btn">
                 <button
                     class="fa fa-plus btn btn-default btn_numeric_step"
                     aria-label="Plus"