salt.utils.xmlutil relies on deprecated Element truth-value testing

Description of Issue

salt/utils/xmlutil.py tests the truth value of xml.etree.ElementTree.Element objects directly (e.g. if not xmltree:, if item:, if ... and parent:), which triggers:

DeprecationWarning: Testing an element's truth value will always return True in future versions.  Use specific 'len(elem)' or 'elem is not None' test instead.

This is emitted on every call to salt.utils.xmlutil.to_dict()/clean_node(), which is used by salt.utils.aws.query() for essentially every AWS API request/response (and therefore by every call made through the ec2 cloud driver, virt XML handling, etc).

This is the same underlying issue as #56475 (getchildren() deprecation in the same file), which was fixed for iteration but not for truth-value testing.

Steps to Reproduce Issue

import warnings
import xml.etree.ElementTree as ET
import salt.utils.xmlutil as xml

with warnings.catch_warnings():
    warnings.simplefilter("error")
    xml.to_dict(ET.fromstring("<parent>data</parent>"))

DeprecationWarning: Testing an element's truth value will always return True in future versions.  Use specific 'len(elem)' or 'elem is not None' test instead.

Or simply run salt-cloud -p <profile> <name> against an ec2 provider and watch the logs.

Versions Report

Reproduced against current master with Python 3.14.

Start in salt/utils/xmlutil.py and inspect the truth-value checks in to_dict() and clean_node(), including the patterns shown in the issue. Run the provided warnings-as-errors reproduction with Python 3.14; done means the conversion completes without a DeprecationWarning while preserving the XML-to-dictionary behavior.