Fix CVE-2025-7962: Upgrade javax.mail from 1.6.2 to jakarta.mail 1.6.4

Co-authored-by: ronaldgyg <214480128+ronaldgyg@users.noreply.github.com>

Author: Copilot

gradle/libs.versions.toml

@@ -36,7 +36,7 @@ mockito-junit-jupiter = { group = "org.mockito", name = "mockito-junit-jupiter",
 junit-jupiter-api = { group = "org.junit.jupiter", name = "junit-jupiter-api", version.ref = "junit-jupiter" }
 junit-jupiter-engine = { group = "org.junit.jupiter", name = "junit-jupiter-engine", version.ref = "junit-jupiter" }
 junit-platform-launcher = { group = "org.junit.platform", name = "junit-platform-launcher", version.ref = "junit-platform" }
-javax-mail = { module = "com.sun.mail:javax.mail", version = "1.6.2" }
+javax-mail = { module = "com.sun.mail:jakarta.mail", version = "1.6.4" }
 
 [plugins]
 spring-boot = { id = "org.springframework.boot", version.ref = "spring-boot" }