`soroban contract invoke` in ledger.json sandbox mode should only output events if `--events` flag is set.

[paulbellamy]

trafficstars

What version are you using?

0.7.1

What did you do?

Followed https://soroban.stellar.org/docs/how-to-guides/events

What did you expect to see?

It printed stuff as the guide says...

What did you see instead?

... but I noticed there is a --events flag. Which seems to do nothing in sandbox mode.

We should be more consistent about error printing with sandbox mode.

We should also update that guide page to show how to read events from the cli more in-depth.