The pricing fetching logic only works for EC2

[Yiwen-Zhang]

Issue:
When running experiment on Bedrock, the uploaded pricing.yml file is not picked up. The function always goes to the pricing_fallback.yml file.

Details:

The pricing function link is designed for EC2. When running Bedrock experiments, after checking EC2 price, the logic goes straight to the pricing_fallback.yml, instead of pricing.yml.