[CI][NIXL] Fix PD CI breakage: pin nixl-cu{12,13} versions (#39851)

Signed-off-by: ZhanqiuHu <zhu@redhat.com>
(cherry picked from commit 799973af

)
Signed-off-by: khluu <khluu000@gmail.com>

requirements/kv_connectors.txt

 lmcache >= 0.3.9
 nixl >= 0.7.1, < 0.10.0 # Required for disaggregated prefill
+nixl-cu12 >= 0.7.1, < 0.10.0
+nixl-cu13 >= 0.7.1, < 0.10.0
 mooncake-transfer-engine >= 0.3.8