Box ShellError in Value::Error (#8375)

# Description

Our `ShellError` at the moment has a `std::mem::size_of<ShellError>` of
136 bytes (on AMD64). As a result `Value` directly storing the struct
also required 136 bytes (thanks to alignment requirements).

This change stores the `Value::Error` `ShellError` on the heap.

Pro:
- Value now needs just 80 bytes
- Should be 1 cacheline less (still at least 2 cachelines)

Con:
- More small heap allocations when dealing with `Value::Error`
  - More heap fragmentation
  - Potential for additional required memcopies

# Further code changes

Includes a small refactor of `try` due to a type mismatch in its large
match.

# User-Facing Changes

None for regular users.

Plugin authors may have to update their matches on `Value` if they use
`nu-protocol`

Needs benchmarking to see if there is a benefit in real world workloads.
**Update** small improvements in runtime for workloads with high volume
of values. Significant reduction in maximum resident set size, when many
values are held in memory.

# Tests + Formatting

crates/nu-explore/src/nu_common/table.rs

@@ -347,7 +347,7 @@ fn convert_to_table2<'a>(
             }
 
             if let Value::Error { error } = item {
-                return Err(error.clone());
+                return Err(*error.clone());
             }
 
             let index = row + row_offset;
@@ -382,7 +382,7 @@ fn convert_to_table2<'a>(
             }
 
             if let Value::Error { error } = item {
-                return Err(error.clone());
+                return Err(*error.clone());
             }
 
             let value = convert_to_table2_entry(
@@ -444,7 +444,7 @@ fn convert_to_table2<'a>(
             }
 
             if let Value::Error { error } = item {
-                return Err(error.clone());
+                return Err(*error.clone());
             }
 
             let value = create_table2_entry(

crates/nu-explore/src/nu_common/value.rs

@@ -52,7 +52,9 @@ fn collect_external_stream(
     let mut data = vec![];
     if let Some(stdout) = stdout {
         let value = stdout.into_string().map_or_else(
-            |error| Value::Error { error },
+            |error| Value::Error {
+                error: Box::new(error),
+            },
             |string| Value::string(string.item, span),
         );
 
@@ -61,7 +63,9 @@ fn collect_external_stream(
     }
     if let Some(stderr) = stderr {
         let value = stderr.into_string().map_or_else(
-            |error| Value::Error { error },
+            |error| Value::Error {
+                error: Box::new(error),
+            },
             |string| Value::string(string.item, span),
         );