Decouple tests from specific encryption implementation

[MrSebastian]

          _:hammer_and_wrench: Refactor suggestion_

Decouple tests from specific encryption implementation

The test contains hardcoded encrypted values which make it brittle to encryption changes.

Consider generating the encrypted values dynamically:

-    private static final String USERNAME_ENCRYPTED = "ENCRYPTED:TLXm2wsx1kcDLHHU8ZWptQ==";
+    @Autowired
+    private CryptoService cryptoService;
+    
+    private String getEncryptedUsername() {
+        return "ENCRYPTED:" + cryptoService.encrypt(USERNAME_UNENCRYPTED);
+    }

Then replace USERNAME_ENCRYPTED usage with getEncryptedUsername() in tests.

Also applies to: 27-27

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⚠️ Potential issue

Security: Remove sensitive test key from source code

Similar to the CryptoServiceIntegrationTest, the encryption key should not be hardcoded.

Move the test key to a secure test configuration file:

-@SpringBootTest(classes = MicroServiceApplication.class, properties = { "service.config.crypto.key=veryLongAndVerySaveKeyIHopeXXXabc123!!" })
+@SpringBootTest(classes = MicroServiceApplication.class)

Committable suggestion skipped: line range outside the PR's diff.

Originally posted by @coderabbitai[bot] in #635 (comment)