fix(cdk/coercion): Return undefined when the fallback value is undefined

Returns undefined when the fallback argument is undefined
for cases where the value is not a number

Fixes #29425

src/cdk/coercion/number-property.ts

@@ -16,7 +16,10 @@ export type NumberInput = string | number | null | undefined;
 export function coerceNumberProperty(value: any): number;
 export function coerceNumberProperty<D>(value: any, fallback: D): number | D;
 export function coerceNumberProperty(value: any, fallbackValue = 0) {
-  return _isNumberValue(value) ? Number(value) : fallbackValue;
+  if (_isNumberValue(value)) {
+    return Number(value);
+  }
+  return arguments.length === 2 ? fallbackValue : 0;
 }
 
 /**