ignore env var set to empty string (#5167)

Author: adhami3310

reflex/config.py

@@ -392,7 +392,7 @@ def getenv(self) -> T | None:
             The environment variable value.
         """
         env_value = os.getenv(self.name, None)
-        if env_value is not None:
+        if env_value and env_value.strip():
             return self.interpret(env_value)
         return None
 
@@ -402,7 +402,7 @@ def is_set(self) -> bool:
         Returns:
             True if the environment variable is set.
         """
-        return self.name in os.environ
+        return bool(os.getenv(self.name, "").strip())
 
     def get(self) -> T:
         """Get the interpreted environment variable value or the default value if not set.
@@ -966,7 +966,7 @@ def update_from_env(self) -> dict[str, Any]:
             env_var = os.environ.get(key.upper())
 
             # If the env var is set, override the config value.
-            if env_var is not None:
+            if env_var and env_var.strip():
                 # Interpret the value.
                 value = interpret_env_var_value(
                     env_var, true_type_for_pydantic_field(field), field.name