[Thread] convert OT_ERROR_INVALID_STATE to INTERNAL_ERROR

In most cases, OT_ERROR_INVALID_STATE in ot-daemon indicates an internal
error. OtDaemonServer should actually maintain the state to make sure no
OT_ERROR_INVALID_STATE error can be returned.

Test: atest CtsThreadNetworkTestCases
Change-Id: I9dd6667548048873bf0c5b8eb85d929dfcaef997