fix: error in truncate command with e2e script (#26443)

e2e-tests/.ci/server.generate.sh

@@ -259,7 +259,7 @@ EOL
 generate_env_files() {
   # Generate .env.server
   mme2e_log "Generating .env.server"
-  truncate --size=0 .env.server
+  truncate -s 0 .env.server
 
   # Setting SERVER-specific variables
   case "$SERVER" in
@@ -287,7 +287,7 @@ generate_env_files() {
   case "$TEST" in
   cypress)
     mme2e_log "Cypress: Generating .env.cypress"
-    truncate --size=0 .env.cypress
+    truncate -s 0 .env.cypress
 
     mme2e_generate_envfile_from_var_names >.env.cypress <<-EOF
 	BRANCH