Promote logConfig of Healthchecks to GA

[modular-magician]

Forgot to apply #3861 to Regional Healthchecks too. That bug is causing diffs with HCs created for HTTPS ILBs

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Release Note Template for Downstream PRs (will be copied)

compute: promoted `log_config` field of `google_compute_health_check` and `google_compute_region_health_check`

compute: set the default value for log_config.enable on `google_compute_region_health_check` to avoid permanent diff on plan/apply. 

Derived from GoogleCloudPlatform/magic-modules#4822