add nil check to nodepool management flattener

[c2thorn]

fixes hashicorp/terraform-provider-google#19895

something must have changed in the backend or this must be a very rare case. This reference hasn't been touched in years

Release Note Template for Downstream PRs (will be copied)

container: fixed a crash in `google_container_node_pool` caused by an occasional nil pointer

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

google provider: Diff ( 1 file changed, 7 insertions(+), 5 deletions(-))
google-beta provider: Diff ( 1 file changed, 7 insertions(+), 5 deletions(-))

[modular-magician]

Tests analytics

Total tests: 212
Passed tests: 199
Skipped tests: 13
Affected tests: 0

Click here to see the affected service packages

• container

🟢 All tests passed!

View the build log