fix(core): treat [class] and [className] as unrelated bindings (#35668)

Before this change `[class]` and `[className]` were both converted into `ɵɵclassMap`. The implication of this is that at runtime we could not differentiate between the two and as a result we treated `@Input('class')` and `@Input('className)` as equivalent.

This change makes `[class]` and `[className]` distinct. The implication of this is that `[class]` becomes `ɵɵclassMap` instruction but  `[className]` becomes `ɵɵproperty' instruction. This means that `[className]` will no longer participate in styling and will overwrite the DOM `class` value.

Fix #35577

PR Close #35668

packages/compiler/src/render3/view/styling_builder.ts

@@ -202,8 +202,7 @@ export class StylingBuilder {
     let binding: BoundStylingEntry|null = null;
     const prefix = name.substring(0, 6);
     const isStyle = name === 'style' || prefix === 'style.' || prefix === 'style!';
-    const isClass = !isStyle &&
-        (name === 'class' || name === 'className' || prefix === 'class.' || prefix === 'class!');
+    const isClass = !isStyle && (name === 'class' || prefix === 'class.' || prefix === 'class!');
     if (isStyle || isClass) {
       const isMapBased = name.charAt(5) !== '.';         // style.prop or class.prop makes this a no
       const property = name.substr(isMapBased ? 5 : 6);  // the dot explains why there's a +1