gh-44376: Write missing namespace declarations in xml.dom.minidom - #156674

…om (pythonGH-156674)

Element.writexml() now writes the xmlns declarations needed for the
namespaces of the element and its attributes, if they are not already
declared for an ancestor.  A prefix in scope is reused for an attribute
in a namespace without a prefix, or a new one is invented, because
attributes cannot use the default namespace.  The document is not
modified by the serialization.

When adding nodes to manifest XML (either the dependency entry
for Common Controls v6, or `trustInfo` -> `security` ->
`requestedPrivileges` -> `requestedExecutionLevel` subtree for
specifying the `level` and `uiAccess` attributes), specify the
namespace; i.e., use the `createElementNS()` method instead of
`createElement()`.

Python 3.16.0a1 started to write the `xmlns` attributes on the XML
elements [1]; so if we add a new element without namespace to an
element that has a namespace (and note that the top-level
`assembly` element in manifest should always have
`urn:schemas-microsoft-com:asm.v1` namespace...), the namespace
on the added element ends up being reset with an added `xmlns=""`
attribute.

Earlier python versions do not write the `xmlns` attributes for
elements added via either `createElementNS()` or `createElement()`,
so for `trustInfo` node, we explicitly created `xmlns` attribute via
`setAttribute()` method. With python 3.16.0a1, this results in both
`xmls=""` and `xmlns="urn:schemas-microsoft-com:asm.v3"` attributes
added to the node; the first one is automatically generated due to
element being added without namespace (hence namespace "reset"),
the second is  due to `setAttribute()` call.

The proper way to resolve this seems to be adding elements with
namespace specified (using `createElementNS()` instead of
`createElement()`); this way, python >= 3.16 keeps track of namespace
changes and automatically adds `xmlns` attributes where needed. And
as long as this matches the manually-added `xmlns` attribute, only
one attribute is added; hence, we can also keep the `setAttribute()`
call to accommodate earlier python versions.

[1] python/cpython#156674