Add GRPC gateway route for listing module and add hard cap setting (backport #2489)

[mergify]

Changelist

Add GRPC query handler for listing module

Test Plan

[Describe how this PR was tested (if applicable)]

Author/Reviewer Checklist

• If this PR has changes that result in a different app state given the same prior state and transaction list, manually add the state-breaking label.
• If the PR has breaking postgres changes to the indexer add the indexer-postgres-breaking label.
• If this PR isn't state-breaking but has changes that modify behavior in PrepareProposal or ProcessProposal, manually add the label proposal-breaking.
• If this PR is one of many that implement a specific feature, manually label them all feature:[feature-name].
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• Manually add any of the following labels: refactor, chore, bug.

Summary by CodeRabbit

• New Features

  • Introduced a new method, marketsHardCap, to query the hard cap number of listed markets.
  • Added an HTTP mapping for the MarketsHardCap RPC method, enabling RESTful access.

• Bug Fixes

  • Enhanced gRPC gateway route registration with context management for improved functionality.
  • Added error handling to the registration process, addressing previous oversight.

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This is an automatic backport of pull request #2489 done by [Mergify](https://mergify.com).