Boxes record for smaller Value enum. (#12252)

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Boxes `Record` inside `Value` to reduce memory usage, `Value` goes from
`72` -> `56` bytes after this change.
# User-Facing Changes
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helps us keep track of breaking changes. -->

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crates/nu-command/src/env/load_env.rs

@@ -58,7 +58,7 @@ impl Command for LoadEnv {
             }
             None => match input {
                 PipelineData::Value(Value::Record { val, .. }, ..) => {
-                    for (env_var, rhs) in val {
+                    for (env_var, rhs) in *val {
                         let env_var_ = env_var.as_str();
                         if ["FILE_PWD", "CURRENT_FILE"].contains(&env_var_) {
                             return Err(ShellError::AutomaticEnvVarSetManually {

crates/nu-command/src/env/with_env.rs

@@ -95,7 +95,7 @@ fn with_env(
                 // single row([[X W]; [Y Z]])
                 match &table[0] {
                     Value::Record { val, .. } => {
-                        for (k, v) in val {
+                        for (k, v) in &**val {
                             env.insert(k.to_string(), v.clone());
                         }
                     }
@@ -123,7 +123,7 @@ fn with_env(
         }
         // when get object by `open x.json` or `from json`
         Value::Record { val, .. } => {
-            for (k, v) in val {
+            for (k, v) in &**val {
                 env.insert(k.clone(), v.clone());
             }
         }