Update quay.io/keycloak/keycloak Docker tag to v26 (#330)

* Update quay.io/keycloak/keycloak Docker tag to v26

* Fix healthcheck for keycloak 26

The healthcheck was failing for two reasons:
1. --health-enabled now defaults to false 
2. It validates HTTP requests more strictly. Thus a bug in the GET
   request from healthcheck.sh was successful in 25.0 but gave a 400
   response in 26.0

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Spencer Bliven <spencer.bliven@gmail.com>

services/backend/services/keycloak/compose.base.yaml

@@ -1,7 +1,7 @@
 services:
   keycloak:
-    image: quay.io/keycloak/keycloak:25.0
-    command: start-dev --import-realm --http-port=80
+    image: quay.io/keycloak/keycloak:26.0
+    command: start-dev --import-realm --health-enabled=true --http-port=80
     env_file: ./config/.env
     volumes:
       - ./healthcheck/healthcheck.sh:/healthcheck.sh

services/backend/services/keycloak/healthcheck/healthcheck.sh

@@ -4,7 +4,7 @@ if ! exec 3<>/dev/tcp/localhost/9000; then
     exit 1
 fi
 
-printf "GET /health/ready HTTP/1.1\r\nHost: localhostConnection: close\r\n\r\n" >&3
+printf "GET /health/ready HTTP/1.1\r\nHost: localhost\r\nConnection: close\r\n\r\n" >&3
 timeout --preserve-status 5 grep -m 1 "UP" <&3
 exit_status=$?
 exec 3>&-