refactor try except block (#1084)

lnbits/extensions/withdraw/lnurl.py

@@ -78,7 +78,7 @@ async def api_lnurl_callback(
         return {"status": "ERROR", "reason": f"Wait {link.open_time - now} seconds."}
 
     usescsv = ""
-    try:
+
     for x in range(1, link.uses - link.used):
         usecv = link.usescsv.split(",")
         usescsv += "," + str(usecv[x])
@@ -106,6 +106,7 @@ async def api_lnurl_callback(
         "usescsv": usecsvback,
     }
 
+    try:
         changes = {
             "open_time": link.wait_time + now,
             "used": link.used + 1,