fix: Adjust pagination limit to be zero-based (#2663)

There isn't a use-case for querying a limit of zero. Using
-1 led to issues when using default parameters for querying.

coderd/database/queries/users.sql

@@ -126,8 +126,8 @@ ORDER BY
     -- a timestamp. This is to ensure consistent pagination.
 	(created_at, id) ASC OFFSET @offset_opt
 LIMIT
-	-- A null limit means "no limit", so -1 means return all
-	NULLIF(@limit_opt :: int, -1);
+	-- A null limit means "no limit", so 0 means return all
+	NULLIF(@limit_opt :: int, 0);
 
 -- name: UpdateUserStatus :one
 UPDATE