Fix idna-mapping-table following Unicode 16 changes

Fix idna-mapping-table following Unicode 16 changes

The latest version of UTS #46 in Unicode 16 has changed the way it
indicates which codepoints are invalid in domain names, causing
'idna-mapping-table' to contain incorrect information, which then breaks
'textsec-domain-suspicious-p' and our test suite.  (Bug#73312)

* admin/unidata/unidata-gen.el (unidata-gen-idna-mapping): Check the
IDNA validity field in "IdnaMappingTable.txt" in addition to checking
the status field, as the latter can now be 'valid' for disallowed
codepoints.

(cherry picked from commit 7d365a2d72d8e656262205827cc5fdf423c3a41f)