Add bot_loop_start() call in plotting.py

plotting.py was missing a call to strategy.bot_loop_start() resulting in strategies using this callback to not work.

Made changes and confirmed plotting now works for strategies using bot_loop_start() callback.

LMK if anything else needed for PR.

freqtrade/plot/plotting.py

@@ -634,6 +634,7 @@ def load_and_plot_trades(config: Dict[str, Any]):
     exchange = ExchangeResolver.load_exchange(config['exchange']['name'], config)
     IStrategy.dp = DataProvider(config, exchange)
     strategy.bot_start()
+    strategy.bot_loop_start()
     plot_elements = init_plotscript(config, list(exchange.markets), strategy.startup_candle_count)
     timerange = plot_elements['timerange']
     trades = plot_elements['trades']