[Java] Upgrade to Mockito 5.15.2.

Author: vyazelenko

gradle/libs.versions.toml

@@ -7,7 +7,7 @@ gradle = "8.11.1"
 
 [libraries]
 agrona = { group = "org.agrona", name = "agrona", version.ref = "agrona" }
-mockito = { group = "org.mockito", name = "mockito-core", version = "5.14.2" }
+mockito = { group = "org.mockito", name = "mockito-core", version = "5.15.2" }
 hamcrest = { group = "org.hamcrest", name = "hamcrest", version = "3.0" }
 jqwik = { group = "net.jqwik", name = "jqwik", version = "1.9.2" }
 json = { group = "org.json", name = "json", version = "20250107" }