fix(platform-browser): Use the right namespace for mathML. (#55622)

Prior to this change, MathML element were created with the wrong namespace resulting in regular DOM `Element`.

This commit fixes this.

Related to #55608 (but doesn't fix it entirely).

PR Close #55622

packages/core/test/acceptance/view_container_ref_spec.ts

@@ -259,7 +259,7 @@ describe('ViewContainerRef', () => {
             'http://www.w3.org/2000/svg',
           );
           expect(fixture.nativeElement.querySelector('math').namespaceURI).toEqual(
-            'http://www.w3.org/1998/MathML/',
+            'http://www.w3.org/1998/Math/MathML',
           );
         });
       }

packages/platform-browser/src/dom/dom_renderer.ts

@@ -35,7 +35,7 @@ export const NAMESPACE_URIS: {[ns: string]: string} = {
   'xlink': 'http://www.w3.org/1999/xlink',
   'xml': 'http://www.w3.org/XML/1998/namespace',
   'xmlns': 'http://www.w3.org/2000/xmlns/',
-  'math': 'http://www.w3.org/1998/MathML/',
+  'math': 'http://www.w3.org/1998/Math/MathML',
 };
 
 const COMPONENT_REGEX = /%COMP%/g;

packages/platform-browser/test/dom/dom_renderer_spec.ts

@@ -252,6 +252,23 @@ describe('DefaultDomRendererV2', () => {
       expect(await styleCount(fixture, '.emulated')).toBe(0);
     });
   });
+
+  describe('should support namespaces', () => {
+    it('should create SVG elements', () => {
+      expect(
+        document.createElementNS(NAMESPACE_URIS['svg'], 'math') instanceof SVGElement,
+      ).toBeTrue();
+    });
+
+    it('should create MathML elements', () => {
+      // MathMLElement is fairly recent and doesn't exist on our Saucelabs test environments
+      if (typeof MathMLElement !== 'undefined') {
+        expect(
+          document.createElementNS(NAMESPACE_URIS['math'], 'math') instanceof MathMLElement,
+        ).toBeTrue();
+      }
+    });
+  });
 });
 
 async function styleCount(