[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

@@ -0,0 +1,83 @@
+/** @odoo-module */
+
+import {registry} from "@web/core/registry";
+import {standardFieldProps} from "@web/views/fields/standard_field_props";
+import {_lt} from "@web/core/l10n/translation";
+import {FloatField} from "@web/views/fields/float/float_field";
+
+export class NumericStep extends FloatField {
+    setup() {
+        super.setup();
+    }
+    _onStepClick(ev) {
+        const $el = $(ev.target).parent().parent().find("input");
+        $el.focus();
+        const mode = $(ev.target).data("mode");
+        this._doStep(mode);
+    }
+    _onKeyDown(ev) {
+        if (ev.keyCode === $.ui.keyCode.UP) {
+            this._doStep("plus");
+        } else if (ev.keyCode === $.ui.keyCode.DOWN) {
+            this._doStep("minus");
+        }
+    }
+    _onWheel(ev) {
+        ev.preventDefault();
+        if (ev.deltaY > 0) {
+            this._doStep("minus");
+        } else {
+            this._doStep("plus");
+        }
+    }
+    updateField(val) {
+        return Promise.resolve(this.props.update(val));
+    }
+    _doStep(mode) {
+        let cval = this.props.value;
+        if (mode === "plus") {
+            cval += this.props.step;
+        } else if (mode === "minus") {
+            cval -= this.props.step;
+        }
+        if (cval < this.props.min) {
+            cval = this.props.min;
+        } else if (cval > this.props.max) {
+            cval = this.props.max;
+        }
+        this.updateField(cval);
+        this.props.setDirty(this._isSetDirty(cval));
+        this.props.setDirty(false);
+    }
+    _isSetDirty(val) {
+        return this.props.value != val;
+    }
+}
+
+NumericStep.template = "web_widget_numeric_step";
+NumericStep.props = {
+    ...standardFieldProps,
+    inputType: {type: String, optional: true},
+    step: {type: Number, optional: true},
+    min: {type: Number, optional: true},
+    max: {type: Number, optional: true},
+    placeholder: {type: String, optional: true},
+};
+
+NumericStep.displayName = _lt("Numeric Step");
+NumericStep.supportedTypes = ["float"];
+NumericStep.defaultProps = {
+    inputType: "text",
+};
+NumericStep.extractProps = ({attrs}) => {
+    return {
+        name: attrs.name,
+        inputType: attrs.options.type,
+        step: attrs.options.step || 1,
+        min: attrs.options.min,
+        max: attrs.options.max,
+        placeholder: attrs.options.placeholder,
+    };
+};
+
+registry.category("fields").add("numeric_step", NumericStep);