FHIR Patient search doesn't work for Unicode family names

[mathias-kogler-snkeos]

Describe the bug FHIR search for FHIR patient resources, that contain Unicode characters in the family name doesn't work.

Environment

Which version of LinuxForHealth FHIR Server? Version: 5.1.1.6 OS: Windows 2022

To Reproduce Steps to reproduce the behavior:

1. POST a FHIR Patient resource containing Unicode characters in the family name to the FHIR server. E.g.,

{
	"resourceType": "Patient",
	"identifier": [
		{
			"system": "myuniquesystem",
			"use": "usual",
			"type": {
				"coding": [
					{
						"system": "http://terminology.hl7.org/CodeSystem/v2-0203",
						"code": "MR"
					}
				]
			},
			"value": "ベッカー"
		}
	],
	"name": [
		{
			"family": "ΤΖΌΖΕΦ"
		}
	],
	"gender": "unknown"
}

3. Try to query for the previously created FHIR Patient resource using /fhir-server/api/v4/Patient?family:contains=ΤΖΌΖΕΦ.
4. An empty FHIR Bundle resource is returned.

Expected behavior The query should return the previously created FHIR Patient resource.

Additional context Querying for FHIR Patient resources via an identifier, that contains Unicode characters, works as expected. E.g., /fhir-server/api/v4/Patient?identifier=myuniquesystem|ベッカー works as expected and returns the previously created FHIR Patient resource.