fix failing api failover tests (#803)

Author: lukasIO

README.md

@@ -131,7 +131,7 @@ try:
         wait_until_answered=True,
     ))
 except api.SipCallError as e:
-    print(e)                    # e.g. "SIP call failed: 486 Busy Here (resource_exhausted)"
+    print(e)                    # e.g. "SIP call failed: 486 Busy Here (failed_precondition)"
     if e.sip_status_code == 486:
         ...                     # busy
 except api.ServerError as e:

tests/api/test_livekitapi.py

@@ -544,7 +544,7 @@ async def _sip_call_error(sip: dict, *, wait: bool = False):
 def test_sip_busy():
     err = asyncio.run(_sip_call_error({"code": 486, "status": "Busy Here"}))
     assert isinstance(err, ServerError)
-    assert err.code == "resource_exhausted"
+    assert err.code == "failed_precondition"
     assert err.sip_status_code == 486
     assert err.sip_status == "Busy Here"
     # printable representation makes the failure clear