fix(ivy): reset style property value defined using [style.prop.px] (#33780)

Prior to this change, setting style prop value to undefined or empty string would not result in resetting prop value in case the style prop is defined using [style.prop.px] syntax. The problem is that the check for empty value (and thus reseting the value) considered successful only in case of `null` value. This commit updates the check to use `isStylingValueDefined` function that also checks for undefined and empty string.

PR Close #33780

packages/core/src/render3/instructions/styling.ts

@@ -585,7 +585,7 @@ function resolveStylePropValue(
   if (value === NO_CHANGE) return value;
 
   let resolvedValue: string|null = null;
-  if (value !== null) {
+  if (isStylingValueDefined(value)) {
     if (suffix) {
       // when a suffix is applied then it will bypass
       // sanitization entirely (b/c a new string is created)