`xml.etree.ElementTree` Deprecation Warnings

[radoering]

I noticed the following deprecation warning when using odxtools with Python 3.12:

odxtools/specialdatagroup.py:25: 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.
    if caption_elem := et_element.find("SDG-CAPTION"):

which is caused by the following line:

odxtools/odxtools/specialdatagroup.py

Line 25 in a602a79

if caption_elem := et_element.find("SDG-CAPTION"):

This can be fixed as follows:

-         if caption_elem := et_element.find("SDG-CAPTION"):
+         if (caption_elem := et_element.find("SDG-CAPTION")) is not None:

There are at least two more similar issues:

odxtools/odxtools/subcomponentparamconnector.py

Line 46 in a602a79

for elem in et_element.find("OUT-PARAM-IF-REFS") or []:

and

odxtools/odxtools/subcomponentparamconnector.py

Line 55 in a602a79

for elem in et_element.find("IN-PARAM-IF-REFS") or []:

which can be fixed similarly, e.g.:

-        for elem in et_element.find("IN-PARAM-IF-REFS") or []:
+        for elem in [] if (in_elems := et_element.find("IN-PARAM-IF-REFS")) is None else in_elems: