fix(price-feeder): Fix gate provider getCandlePrices

[zarazan]

• Fix the gate providers getCandlePrices function to use the correct currency pair string for the stored map of candles
• Updates the price-feeder integration test to use our current sample config
• Removes the noisy websocket send message logger - only log when subscription messages are sent (excludes heartbeat/ping messages)

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[rbajollari]

🔥