mgr/dashboard: Change side navigation to `Overview`

mgr/dashboard: Change side navigation to `Overview`

Fixes https://tracker.ceph.com/issues/73318

Signed-off-by: Afreen Misbah <afreen@ibm.com>
(cherry picked from commit 828802d21a1b5eb4d99e4b461bcd50b30538eb17)

 Conflicts:
	src/pybind/mgr/dashboard/frontend/cypress/e2e/a11y/dashboard.e2e-spec.ts
	src/pybind/mgr/dashboard/frontend/cypress/e2e/orchestrator/04-osds.e2e-spec.ts
	src/pybind/mgr/dashboard/frontend/cypress/e2e/ui/dashboard-v3.e2e-spec.ts
	src/pybind/mgr/dashboard/frontend/src/app/ceph/dashboard/dashboard/dashboard.component.html
	src/pybind/mgr/dashboard/frontend/src/app/ceph/dashboard/dashboard/dashboard.component.ts
	src/pybind/mgr/dashboard/frontend/src/app/core/navigation/navigation/navigation.component.html
	src/pybind/mgr/dashboard/frontend/src/app/shared/enum/cell-template.enum.ts
	src/pybind/mgr/dashboard/frontend/src/styles/ceph-custom/_spacings.scss