disable rich exception output in console for API by default, use WEBUI_RICH_EXCEPTIONS env var to enable

modules/api/api.py

@@ -1,5 +1,6 @@
 import base64
 import io
+import os
 import time
 import datetime
 import uvicorn
@@ -98,14 +99,16 @@ def encode_pil_to_base64(image):
 
 
 def api_middleware(app: FastAPI):
-    rich_available = True
+    rich_available = False
     try:
+        if os.environ.get('WEBUI_RICH_EXCEPTIONS', None) is not None:
             import anyio  # importing just so it can be placed on silent list
             import starlette  # importing just so it can be placed on silent list
             from rich.console import Console
             console = Console()
+            rich_available = True
     except Exception:
-        rich_available = False
+        pass
 
     @app.middleware("http")
     async def log_and_time(req: Request, call_next):