update default_config with new defaults (#11856)

# Description

Update a few defaults.
1. use_ls_colors_completeions defaults to true.
2. make ide_menu only offer 10 completions at a time with
`max_completion_height = 10` instead of taking the entire screen.

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crates/nu-utils/src/sample_config/default_config.nu

@@ -212,7 +212,7 @@ $env.config = {
             max_results: 100 # setting it lower can improve completion performance at the cost of omitting some options
             completer: null # check 'carapace_completer' above as an example
         }
-        use_ls_colors: false # set this to true to enable file/path/directory completions using LS_COLORS
+        use_ls_colors: true # set this to true to enable file/path/directory completions using LS_COLORS
     }
 
     filesize: {
@@ -280,7 +280,7 @@ $env.config = {
                 layout: ide
                 min_completion_width: 0,
                 max_completion_width: 50,
-                # max_completion_height: 10, # will be limited by the available lines in the terminal
+                max_completion_height: 10, # will be limited by the available lines in the terminal
                 padding: 0,
                 border: true,
                 cursor_offset: 0,