fix(multichain-network-controller): batch requests for active networks

[vinnyhoward]

Explanation

This PR implements request batching for the Network Activity API to accommodate a new limitation imposed by the API platform team. The API endpoint now caps requests at 20 account IDs per call to prevent URL length limitations in some browsers.

Key Changes

• Modified MultichainNetworkService to handle batching of account IDs in groups of 20
• Added internal batch processing logic to maintain the same public interface
• Updated tests to validate correct batching behavior

References

Related to #4469

Changelog

NA

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes