test(udm-rest-api): fix 73_udm-rest/01_openapi_validation

It was caused by the new [4.6 version of typing-extensions](https://github.com/python/typing_extensions/blob/main/CHANGELOG.md#release-460-may-22-2023) used by jsonschema-spec to validate protocol.

>    isinstance() checks against runtime-checkable protocols now use inspect.getattr_static() rather than hasattr() to lookup whether attributes exist (backporting python/cpython#103034). This means that descriptors and getattr methods are no longer unexpectedly evaluated during isinstance() checks against runtime-checkable protocols. However, it may also mean that some objects which used to be considered instances of a runtime-checkable protocol on older versions of typing_extensions may no longer be considered instances of that protocol using the new release, and vice versa. Most users are unlikely to be affected by this change. Patch by Alex Waygood.

Temporary workaround will be downgrading typing-extensions to version below 4.6:

    pip install "typing-extensions<4.6"

Bug #50048

test/ucs-test/debian/changelog

@@ -1,3 +1,9 @@
+ucs-test (10.0.11-1) unstable; urgency=medium
+
+  * Bug #50048: fix 73_udm-rest/01_openapi_validation
+
+ -- Florian Best <best@univention.de>  Sat, 10 Jun 2023 13:58:22 +0200
+
 ucs-test (10.0.10-69) unstable; urgency=medium
 
   * Bug #31388: add "read list" to 53_samba-common/10samba-share-options

test/ucs-test/tests/73_udm-rest/01_openapi_validation

@@ -23,6 +23,8 @@ cleanup() {
 trap cleanup INT TERM EXIT
 
 python3 -m pip install -U pip
-python3 -m pip install openapi-spec-validator==0.4.0
+python3 -m pip install "typing-extensions<4.6"
+python3 -m pip install openapi-spec-validator
+
 
 curl -u "$(ucs_convertDN2UID ${tests_domainadmin_account})":"${tests_domainadmin_pwd}" http://localhost/univention/udm/openapi.json | python3 -m openapi_spec_validator - || fail_fast 1