Inlet: messages output should not include sidre root

Users can put the Inlet tree of information under any root of the Sidre Datastore. When outputting error messages that root should not be in the user facing messages. For example, if the user gives a sidre root of `inlet_root` then a warning/error may end up with:

```
[Inlet] Field failed lambda verification: inlet_root/some/user/defined/field
```

when it should be:

```
[Inlet] Field failed lambda verification: some/user/defined/field
```

Start by locating Inlet's user-facing warning and error message generation and how the Sidre root is included in reported paths. Reproduce the shown inlet_root/... case, then verify that messages retain only the user-defined path.

Written by the indexing model from the issue text.