Fix: Only set description field when not empty to avoid Terraform validation errors

The description field was being set unconditionally in resourceRoleRead,
which caused Terraform to reject the plan when the description was empty
because it was trying to set a non-computed attribute to an empty string.

This fix ensures that the description field is only set when it contains
actual content, preventing the 'Provider produced invalid plan' error
for elasticstack_kibana_security_role resources without descriptions.

Fixes: elastic#1186

Author: snobear

internal/kibana/role.go

@@ -350,8 +350,11 @@ func resourceRoleRead(ctx context.Context, d *schema.ResourceData, meta interfac
 	if err := d.Set("kibana", flattenKibanaRoleKibanaData(&role.Kibana)); err != nil {
 		return diag.FromErr(err)
 	}
-	if err := d.Set("description", role.Description); err != nil {
-		return diag.FromErr(err)
+	// Only set description if it's not empty to avoid Terraform validation errors
+	if strings.TrimSpace(role.Description) != "" {
+		if err := d.Set("description", role.Description); err != nil {
+			return diag.FromErr(err)
+		}
 	}
 	if role.Metadata != nil {
 		metadata, err := json.Marshal(role.Metadata)