aws explorer: use consistent page size for "More..."

Problem:

ECS, CloudWatch Logs, S3, etc., have their own pages sizes. E.g. https://github.com/aws/aws-toolkit-vscode/pull/2367

Solution:

1. All services should use one consistent page size
2. To avoid a regression of https://github.com/aws/aws-toolkit-vscode/pull/2367 , add a type check or assert (or change ECS listing to handle more than 10 describe results)

Start by reviewing the AWS Explorer pagination code for ECS, CloudWatch Logs, and S3, then compare their page sizes with pull request #2367. Check how ECS handles more than 10 describe results and identify a consistent page-size rule. Done means all listed services use the same size without regressing the ECS listing behavior.

Written by the indexing model from the issue text.