fix: AWS PlacementeScoreData API not supported

[adrianriobo]

Previously we use the target region for the data as the region to access the API, but some regions do not offer the API, which is different from not having data for the PlacementScore in that region. This commit ensures all API calls to get the data are made to a fixed region where we know the API is available. Fix #602

[adrianriobo]

@ppitonak if you test this one can you ack here?

[ppitonak]

Before this change, I was messages like the one below and some regions were skipped, such as il-central-1

[33mWARN�[0m operation error EC2: GetSpotPlacementScores, https response error StatusCode: 400, RequestID: 6dc0880b-30ca-43cd-bf66-7747646c3558, api error UnsupportedOperation: The functionality you requested is not available in this region. 

With this change, the message for regions with no data changed

�[33mWARN�[0m non available scores  

but I see that il-central-1 was checked

�[37mDEBU�[0m Found InstanceType g5.12xlarge at Availability Zone il-central-1c with spot price 3.477300 

I guess that it works as expected.

[ppitonak]

Merging is blocked
Commits must have verified signatures.