fix(compute-mig): add mode property to compute_region_autoscaler

[NotArpit]

Description

The compute-mig module at //modules/compute-mig takes in the mode property via the variable autoscaler_config but does not propagate it to the google_compute_autoscaler and google_compute_region_autoscaler resources in autoscaler.tf.

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Checklist

I applicable, I acknowledge that I have:

• Read the contributing guide
• Ran terraform fmt on all modified files
• Regenerated the relevant README.md files using tools/tfdoc.py
• Made sure all relevant tests pass

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[juliocc]

Nice catch.

Can you sign the CLA so we can merge this?

[NotArpit]

Can you sign the CLA so we can merge this?

Done.