test(e2e): add multi-GPU MIG profile coverage

[karenychen]

What this PR does / why we need it:

Adds an Ubuntu 24.04 E2E scenario that applies the MIG2g profile to a multi-GPU Standard_ND96asr_v4 VM and validates the full VM-wide result:

• NVIDIA Fabric Manager and device plugin services are running
• MIG mode is enabled on all 8 A100 GPUs
• 24 MIG 2g.10gb instances are created
• the node advertises nvidia.com/gpu=24
• a MIG workload can be scheduled

The shared MIG validators now assert exact GPU and MIG-instance counts, so the test cannot pass after partitioning only one card. Existing single-GPU MIG scenarios were updated to use the same exact-count validation.

Which issue(s) this PR fixes:

Fixes #

Testing:

• cd e2e && go test ./... -run "^$" -count=1
• git diff --check