feat(android): optimize Ti.Preferences

[m1ga]

Optimizing the Ti.Preferences code a bit not to rely on try/catch.

getPreference(String key) Two issues here:

• systemProperties.get(key) throws JSONException for every non-tiapp.xml key
• preferences.getAll().get(key) loads the entire preference map into memory on every call, even when the key doesn't exist

Fix: Use has() instead of try/catch. Guard getAll() with contains().

Test code

Ti.App.Properties.setString('givenName', 'Paul');
console.log('The value of the givenName property is: ' + Ti.App.Properties.getString('givenName'));

Ti.App.Properties.setBool('boolValue', true);
console.log('boolValue', Ti.App.Properties.getBool('boolValue', false));

console.log('boolValueDefault1', Ti.App.Properties.getBool('boolValueDefault1', false));
console.log('boolValueDefault2', Ti.App.Properties.getBool('boolValueDefault2'));

// get all
var props = Ti.App.Properties.listProperties();
for (var i = 0, ilen = props.length; i < ilen; i++) {
	var value = Ti.App.Properties.getString(props[i]);
	console.log(props[i] + ' = ' + value);
}

[hansemannn]

Reviewed the current PR diff (TiProperties.java only). I do not see a blocking regression: system properties still take precedence, preference fallback remains for missing or mismatched typed values, and git diff --check is clean. I did not run the Android test suite.