dashboard grafana integration hardcodes dashboard datasource

https://github.com/ceph/ceph/commit/527f76005cb3

Updated the iframe based integration between the dashboard and grafana to pass the datasource to use for the grafana dashboard - this is passed as the hardcoded literal 'Dashboard1' which means that unless the data source in grafana matches this key, the iframe based panels will not work.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ceph-mgr-dashboard 16.2.6-0ubuntu0.21.04.1~cloud0 [modified: usr/share/ceph/mgr/dashboard/frontend/src/app/shared/components/grafana/grafana.component.ts] [origin: Canonical]
ProcVersionSignature: Ubuntu 5.4.0-91.102-generic 5.4.151
Uname: Linux 5.4.0-91-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.21
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB:
 {
                "impl": "launchpad",
                "project": "cloud-archive",
                "bug_pattern_url": "http://people.canonical.com/~ubuntu-archive/bugpatterns/bugpatterns.xml",
             }
Date: Mon Dec 6 16:05:45 2021
PackageArchitecture: all
ProcEnviron:
 TERM=screen-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
 SHELL=/bin/bash
SourcePackage: ceph
UpgradeStatus: No upgrade log present (probably fresh install)