fix(cli/rm/rm.go): using panic is not user friendly (#1608)

I manually tested the cli and concluded that it's too easy to reach the
panic caused by runtimex.Try0 over there and it would expose panics to
users too frequently.

Let's just convert those into normal error checks. Here is what we would
previously get:

```
% ./ooniprobe rm
? Are you sure you wish to delete the result #0  [Use arrows to move, type to filter]
  true
> false
panic: Try0: interrupt

[...]
```

So, here I just pressed ^D and got a panic. Ouch!

After the diff, we have this:

```
% ./ooniprobe rm
? Are you sure you wish to delete the result #0 false
   ⨯ failure in main command   error=canceled by user
```

and:

```
% ./ooniprobe rm --all
? Are you sure you wish to delete ALL results false
   ⨯ failure in main command   error=canceled by user
```

It seems much better, isn't it?

Part of the QA for ooni/probe#2722

cmd/ooniprobe/internal/cli/rm/rm.go

@@ -9,7 +9,6 @@ import (
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/cmd/ooniprobe/internal/cli/root"
 	"github.com/ooni/probe-cli/v3/internal/database"
-	"github.com/ooni/probe-cli/v3/internal/runtimex"
 	"github.com/upper/db/v4"
 )
 
@@ -21,7 +20,7 @@ func deleteAll(d *database.Database, skipInteractive bool) error {
 			Options: []string{"true", "false"},
 			Default: "false",
 		}
-		runtimex.Try0(survey.AskOne(confirm, &answer, nil))
+		_ = survey.AskOne(confirm, &answer, nil) // no error checking: we rely on the default value
 		if answer == "false" {
 			return errors.New("canceled by user")
 		}
@@ -81,7 +80,7 @@ func init() {
 			Options: []string{"true", "false"},
 			Default: "false",
 		}
-		runtimex.Try0(survey.AskOne(confirm, &answer, nil))
+		_ = survey.AskOne(confirm, &answer, nil) // no error checking: we rely on the default value
 		if answer == "false" {
 			return errors.New("canceled by user")
 		}