Check if nodepool created before returning error

[modular-magician]

Current implementation of GKE_STOCKOUT not being captured in state issue from #6287 doesn't seems to work.
Error during apply is as follows:
Error: Error waiting for creating GKE NodePool: Google Compute Engine: Not all instances running in IGM after 1m6.219216581s. Expected 40, running 1, transitioning 39. Current errors: [GCE_STOCKOUT]: Instance 'instance' creation failed: The zone 'projects/redacted/zones/us-west1-b' does not have enough resources available to fulfill the request. '(resource type:compute)'.; (truncated).

GCP behavior is to create a node pool in error state and keep waiting for resources to show up. This cause the node pool to be created but this fact is not captured in the state since error is returned.

In order to fix this bug I'm proposing to re-check if node pool exist instead of simply assuming that it doesn't. This approach will prevent any type of situation like that, since the whole flow will be as follow:

• ensure node pool doesn't exist
• create the node pool
• if error, check if exist
• if exist - capture that in state
• if doesn't - return error

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Release Note Template for Downstream PRs (will be copied)

container: fixed an issue where a node pool created with error (eg. GKE_STOCKOUT) would not be captured in state

Derived from GoogleCloudPlatform/magic-modules#5225

[github-actions]

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