Fix ICU tests on alpine / macOS. (#15177)

The word boundary behaviour is slightly different, consider it
acceptable for the tests.

changelog.d/15177.bugfix

@@ -0,0 +1 @@
+Fix test_icu_word_boundary_punctuation for alpine / macos installed ICU versions.

tests/storage/test_user_directory.py

@@ -696,6 +696,8 @@ class UserDirectoryICUTestCase(HomeserverTestCase):
                 ["lazy'fox", "jumped", "over", "the", "dog"],
                 # ICU 70 on Ubuntu 22.04
                 ["lazy'fox", "jumped:over", "the.dog"],
+                # pyicu 2.10.2 on Alpine edge / macOS
+                ["lazy'fox", "jumped", "over", "the.dog"],
             ),
         )