panel not working when change SRSIM to 26.7.R1

[sepion]

when change image panel show error "Backend Disconnected"

image: registry.srlinux.dev/pub/nokia_srsim:25.10.R1
new image
image: registry.srlinux.dev/pub/nokia_srsim:26.7.R1

[tiago-amado]

R26 introduces gnmi path changes, so both the panel and the grafana dashboards must be updated. a new panel package must be created.