fix: RPC endpoint always return stacks canonical height

[Jiloc]

Description

The X-Canonical-Stacks-Tip-Height header is intended to be included in all succesfull RPC responses, and this has mostly been the case until epoch 2.5. However, over time this behavior was inconsistently applied, as the header had to be manually added in each endpoint's implementation. This made it easy to forget during implementation or review of new endpoints.

This PR refactors the code to centralize the logic for setting this header, ensuring it is automatically included in all relevant responses. So we eliminate the need to manually include it in each endpoint and write dedicated tests for it for each new endpoint. The presence of the header continues to be covered by existing integration tests for various endpoints (e.g.,

stacks-core/stackslib/src/net/api/tests/getinfo.rs

Lines 90 to 93 in 9d53951

	assert_eq!(
	response.preamble().get_canonical_stacks_tip_height(),
	Some(1)
	);

)

The following endpoints were previously missing the header and are now covered:

• /v2/blocks/:block_id
• /v2/headers/:height
• /v2/mempool/query
• /v2/microblock/*
• /v3/tenures/fork_info
• /v3/blocks/:block_id
• /v3/blocks/height/:block_height
• /v3/health
• /v3/sortitions/*
• /v3/tenures/:block_id
• /v3/tenures/info
• /v3/tenures/tip/:consensus_hash
• /v3/transaction/:txid

This change also lays the groundwork for a follow-up PR that will use this header to determine the highest Stacks tip height among peers via their RPC responses.

Other changes:

• the various HttpPreambleExtensions functions to set the header now expect a u64 instead of a u32, avoiding the u64 -> u32 casting.
• add a is_success function to HttpResponsePreamble to easily check the response header.

Applicable issues

• fixes #

Additional info (benefits, drawbacks, caveats)

Checklist

• Test coverage for new or modified code paths
• Changelog is updated
• Required documentation changes (e.g., docs/rpc/openapi.yaml and rpc-endpoints.md for v2 endpoints, event-dispatcher.md for new events)
• New clarity functions have corresponding PR in clarity-benchmarking repo
• New integration test(s) added to bitcoin-tests.yml