Fix GH-8538: SoapClient may strip parts of nmtokens

When stripping the namespace prefix, we can assume that this does not
contain any colons, while the rest of the name may contain colon

Fix GH-8538: SoapClient may strip parts of nmtokens

When stripping the namespace prefix, we can assume that this does not
contain any colons, while the rest of the name may contain colons.
Hence we must not use `strrchr()` but rather `strchr()` instead.

Closes GH-8543.

show more ...