Fix LDAP test crash #7236

Job	Run time
Build doc	6m 19s
CodeQL analysis	3m 12s
pyca/cryptography test	31s
Code health check	1m 6s
Type hints check	30s
Check SPDX identifiers	7s
ubuntu-latest 3.7 non_root -K scanner	3m 46s
ubuntu-latest 3.8 non_root -K scanner	4m 15s
ubuntu-latest 3.9 non_root -K scanner	4m 9s
ubuntu-latest 3.10 non_root -K scanner	4m 14s
ubuntu-latest 3.11 non_root -K scanner	5m 37s
ubuntu-latest 3.12 non_root -K scanner	4m 29s
ubuntu-latest 3.12 root -K scanner	7m 14s
ubuntu-latest pypy3.9 root -K scanner	4m 27s
ubuntu-latest libpcap 3.12 root -K scanner	5m 39s
macos-14 3.12 both -K scanner	5m 34s
ubuntu-latest 3.12 root -k scanner	4m 36s
ubuntu-latest pypy3.9 root -k scanner	3m 33s
macos-14 3.12 both -k scanner	1m 23s
	1h 10m 41s

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