fix: try_many_times: retry 5 times instead of 60

[WofWca]

If 5 times is not enough, 60 will probably not be enough either.

This is mainly an attempt of improving the situation with https://github.com/deltachat/deltachat-desktop/issues/3959.

The remove_account RPC call would make the RPC server stop responding to all other requests, which is basically equivalent to a one minute hang.

Additionally, try_many_times appears to be unnecessary after https://github.com/chatmail/core/pull/5814#issuecomment-2257164502.

[iequidoo]

The remove_account RPC call would make the RPC server stop responding to all other requests, which is basically equivalent to a one minute hang.

The write lock isn't actually needed for the whole time of an account removal, i think this may be fixed separately. But i agree that 60 s is too much, better if the user receives feedback earlier and retries the removal if needed.