Kamal "inlines" calls to `kamal secrets` in the dotenv file, but the
results of the calls were not being escaped properly. To "fix" this
`kamal secrets fetch` escaped the JSON string before returning it.
The two errors cancelled out, but it meant that the commands didn't
work from a shell.
To fix, we'll escape the inline command results and remove the escaping
from `kamal secrets fetch`.
Avoid outputting this login error message, it wasn't an error and you
don't need to follow those instructions.
```
[ERROR] 2024/09/11 11:57:08 You are not currently signed in. Please run `op signin --help` for instructions
```
Rather than redirecting the global $stdout, which is not never clever in
a threaded program, we'll make the secrets commands aware they are
being inlined, so they return the value instead of printing it.
Additionally we no longer need to interrupt the parent process on error
as we've inlined the command - exit 1 is enough.
