refactor: replace anonymous class with bound closure in PropertiesTrait

[paulbalandan]

Description
This one needs a bit of decision.

This refactors PropertiesTrait::getPublicProperties() to use a bound Closure instead of an anonymous class in order to delete the 1 remaining missingType.iterableValue error. The other solution was to use reflection similar to getNonPublicProperties() approach, but here's the bench:

200k iterations each, on an object with 5 public + 1 protected + 1 private property:

Approach	Time	Per call
Anonymous class	0.2721s / 0.2815s	~1.4μs
Bound closure	0.3541s	~1.77μs
Reflection	1.2148s / 1.2236s	~6.1μs

Bound closure is ~26% slower than the anonymous class but ~3.5x faster than reflection.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[datamweb]

This approach looks good.

[michalsn]

The difference is minimal.