Use imported names in Command::run signatures (#7967)

# Description

_(Thank you for improving Nushell. Please, check our [contributing
guide](../CONTRIBUTING.md) and talk to the core team before making major
changes.)_

I opened this PR to unify the run command method. It's mainly to improve
consistency across the tree.

# User-Facing Changes

None.

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/strings/char_.rs

@@ -1,6 +1,7 @@
 use indexmap::indexmap;
 use indexmap::map::IndexMap;
 use nu_engine::CallExt;
+use nu_protocol::engine::{EngineState, Stack};
 use nu_protocol::{
     ast::Call, engine::Command, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData,
     PipelineData, ShellError, Signature, Span, SyntaxShape, Type, Value,
@@ -211,11 +212,11 @@ impl Command for Char {
 
     fn run(
         &self,
-        engine_state: &nu_protocol::engine::EngineState,
-        stack: &mut nu_protocol::engine::Stack,
+        engine_state: &EngineState,
+        stack: &mut Stack,
         call: &Call,
         _input: PipelineData,
-    ) -> Result<nu_protocol::PipelineData, ShellError> {
+    ) -> Result<PipelineData, ShellError> {
         let call_span = call.head;
         // handle -l flag
         if call.has_flag("list") {