Remove custom svg transformer for tests

Use the default one provided by sewing-kit. We're about to change how
icons get loaded so there's no point having a transformer that mimics
the old way.

The only reason why we needed it was for some Spinner tests, which can
be expressed in a different way

sewing-kit.config.ts

@@ -16,14 +16,6 @@ export default function sewingKitConfig(
 
         config.setupFiles.push(join(tests, 'setup.ts'));
 
-        // svg transform have to go before the existing transforms so that .svg
-        // files match our declaration first, and thus run the svg transform,
-        // instead of matching the file transform
-        config.transform = {
-          '\\.svg$': join(__dirname, 'config/jest/transformers/svg.js'),
-          ...config.transform,
-        };
-
         // Code coverage
         config.collectCoverageFrom = [
           'src/**/*.{ts,tsx}',

src/components/Spinner/tests/Spinner.test.tsx

@@ -15,24 +15,24 @@ describe('<Spinner />', () => {
   describe('size', () => {
     it('renders a large spinner by default', () => {
       const spinner = shallowWithAppProvider(<Spinner />);
-      expect(spinner.find('svg').prop('viewBox')).toBe('0 0 44 44');
+      expect(spinner.find('svg').hasClass('sizeLarge')).toBeTruthy();
     });
 
     it('renders a large spinner when size is large', () => {
       const spinner = shallowWithAppProvider(<Spinner size="large" />);
-      expect(spinner.find('svg').prop('viewBox')).toBe('0 0 44 44');
+      expect(spinner.find('svg').hasClass('sizeLarge')).toBeTruthy();
     });
 
     it('renders a small spinner when size is small', () => {
       const spinner = shallowWithAppProvider(<Spinner size="small" />);
-      expect(spinner.find('svg').prop('viewBox')).toBe('0 0 20 20');
+      expect(spinner.find('svg').hasClass('sizeSmall')).toBeTruthy();
     });
 
     it('renders a small spinner when color is white even if size is large', () => {
       const spinner = shallowWithAppProvider(
         <Spinner size="large" color="white" />,
       );
-      expect(spinner.find('svg').prop('viewBox')).toBe('0 0 20 20');
+      expect(spinner.find('svg').hasClass('sizeSmall')).toBeTruthy();
     });
   });