CLSA-2026-1777366733 python3: Fix of CVE-2026-1299

CVE-2026-1299: reject newline injection in email module's BytesGenerator when serializing headers - Skip test.testxmletree.XMLPullParserTest.testsimplexml during RPM build; unrelated expat-2.1.0-15.0.7.tuxcare.els1 regression breaks XMLPullParser chunked-feed semantics in TuxCare ELS el7 build...