[TextField] Added new prop that disables spinner

UNRELEASED.md

@@ -8,6 +8,8 @@ Use [the changelog guidelines](https://git.io/polaris-changelog-guidelines) to f
 
 ### Enhancements
 
+Updated `Textfield` with a `type` of `number` to not render a spinner if step is set to `0` ([#3477](https://github.com/Shopify/polaris-react/pull/3477))
+
 ### Bug fixes
 
 ### Documentation

src/components/TextField/TextField.tsx

@@ -340,7 +340,7 @@ export function TextField({
   );
 
   const spinnerMarkup =
-    type === 'number' && !disabled && !readOnly ? (
+    type === 'number' && step !== 0 && !disabled && !readOnly ? (
       <Spinner
         onChange={handleNumberChange}
         onMouseDown={handleButtonPress}

src/components/TextField/tests/TextField.test.tsx

@@ -704,6 +704,20 @@ describe('<TextField />', () => {
         expect(element.find(Spinner)).toHaveLength(0);
       });
 
+      it('removes spinner buttons when type is number and step is 0', () => {
+        const spy = jest.fn();
+        const element = mountWithAppProvider(
+          <TextField
+            id="MyNumberField"
+            label="NumberField"
+            type="number"
+            step={0}
+            onChange={spy}
+          />,
+        );
+        expect(element.find(Spinner)).toHaveLength(0);
+      });
+
       it('increments by step when value, step, or both are float numbers', () => {
         const spy = jest.fn();
         const element = mountWithAppProvider(