checkupdates: Ignore xml tags in string content

checkupdates: Ignore xml tags in string content

This allows us to fetch strings like the following:

<string name="app_name">foo <xliff:g>bar</xliff:g></string>

Up until now, using .text would only return "foo ", but if we use .tostring()
with the text method, it converts everything into plain text for us resulting
in "foo bar".