[JetStream] Replace StringConstants object with string resources

- `StringConstants` object in referred from several files, to set the labels for some components, for example
- Most of the code referring to the object should be replaced with the ones to refer to string resources with `stringResource`

Locate the JetStream StringConstants object and the several files that refer to it. Review the existing string resources and stringResource usages, then confirm that component labels use those resources and that the old object is no longer referenced.

Written by the indexing model from the issue text.