Pin synapse-api to main (2.4.1) and support peripheral_id in impedance queries

[calvinleng-science]

Summary

• Pin the synapse-api submodule to the current head of main (cacec78), which adds peripheral_id (uint32, field 2) to ImpedanceQuery and bumps the API version to 2.4.1
• Restamp synapse/_api_version.py to 2.4.1 (generated from the submodule's VERSION file)
• Log the queried peripheral in the CLI impedance stream handler
• Add a peripheral_id entry to the example test_query.json
• Bump package version to 2.7.3

Since the Python bindings are generated from the submodule at build time and the CLI parses query JSON directly into the proto, a "peripheral_id" entry in a query file flows through synapsectl query automatically once the submodule is repinned.

Test plan

• pytest passes (24 tests)
• Verified the regenerated proto parses peripheral_id from query JSON