Include resend as a default dependency, rather than restricting to prod

src/khoj/routers/email.py

@@ -1,12 +1,8 @@
 import logging
 import os
 
-try:
-    import resend
-except ImportError:
-    pass
-
 import markdown_it
+import resend
 from django.conf import settings
 from jinja2 import Environment, FileSystemLoader
 
@@ -23,7 +19,7 @@ static_files = os.path.join(settings.BASE_DIR, "static")
 env = Environment(loader=FileSystemLoader(static_files))
 
 if not RESEND_API_KEY:
-    logger.warn("RESEND_API_KEY not set - email sending disabled")
+    logger.warning("RESEND_API_KEY not set - email sending disabled")
 else:
     resend.api_key = RESEND_API_KEY