Use beta provider in runtimeconfig test

[slevenick]

This is beta-only now, so the test needs to use the beta provider explicitly. Fixes IAM tests as well

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[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform Beta: Diff ( 9 files changed, 13 insertions(+), 5 deletions(-))

[slevenick]

/gcbrun

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform Beta: Diff ( 1 file changed, 5 insertions(+))