CloudFormation formatter does not respect chosen indentation

https://github.com/aws/aws-toolkit-vscode/blob/22be93735bb20c22cefaef407ecfef7d7b7f72b9/packages/core/src/awsService/cloudformation/commands/cfnCommands.ts#L343

This is hardcoded to `2` regardless of the indentation chosen in the VSCode editor.

## Expected

When I pick a certain indentation in VSCode, I expect the formatter to respect it.

## Actual

When formatting CloudFormation YAML file, the items are reindented using a "tab" size of 2, even when I selected indentation size 4. When I have all my CloudFormation YAMLs with a certain indentation size, enabling this VSCode extension suddenly changes the entire file, forcing me to enable/disable the extension to avoid unnecessary churn on files.

Start at packages/core/src/awsService/cloudformation/commands/cfnCommands.ts, around line 343, where the issue says indentation is hardcoded to 2. Check how the formatter can access the VSCode editor's chosen indentation; done means formatting a CloudFormation YAML file respects the selected size, including size 4.

Written by the indexing model from the issue text.