Add limit and page fields to PubSub and Webhooks List RPC

[halimi]

Summary

References: #7418
References: https://github.com/TheThingsIndustries/lorawan-stack-support/issues/1222

This PR fixes the ApplicationPubSubRegistry/List and ApplicationWebhookRegistry/List default pagination limit feature.

Changes

• Add limit and page fields to PubSub and Webhooks List RPC
• Set pagination values in PubSub and Webhooks List RPC

Testing

Steps

See the test steps in #7418

Results

Regressions

...

Notes for Reviewers

This is fixes the issue found during release testing. https://github.com/TheThingsIndustries/lorawan-stack-support/issues/1222#issuecomment-2684962799
Probably needs to cherry-pick to the v3.34 release branch.

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Testing: The steps/process to test this feature are clearly explained including testing for regressions.
• Infrastructure: If infrastructural changes (e.g., new RPC, configuration) are needed, a separate issue is created in the infrastructural repositories.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.