Create `try_get_text` helper function in parse_xml

[AdrianDAlessandro]

This pattern seems

to be quite common. A little helper function might help with readability here and elsewhere:

def try_get_text(soup: BeautifulSoup, name: str, attrs: dict[str, str]) -> str:
    if result := soup.find(name, attrs):
        return result.text
    return ""

Originally posted by @alexdewar in #263 (comment)