Ignored "raw" flag for StockDataStream

# Issue
Initializing StockDataStream with parameter ```raw_data=True``` creates a websocket that returns timestamp as 'Timestamp', instead of the RAW string with the datetime.

# Replicate
~~~python
from alpaca.data.live.stock import StockDataStream

wss_client = StockDataStream('api-key', 'secret-key', raw_data=True)

# async handler
async def quote_data_handler(data: Any):
# quote data will arrive here
print(data)
print("===")

wss_client.subscribe_quotes(quote_data_handler, "AAPL")

wss_client.run()
~~~
output:

Expected output (from https://alpaca.markets/docs/api-references/market-data-api/stock-pricing-data/realtime/):