Fix copy shortcut in macOS notebook cells (#59431)

Fix `cmd-c` not copying text inside macOS notebook cell editors.

Previously, the macOS notebook keymap bound `cmd-c` to
`notebook::InterruptKernel` in notebook contexts, including
`NotebookEditor > Editor`. This shadowed the normal editor copy shortcut
while editing notebook cells.


## Solution

Move the macOS notebook interrupt shortcut from `cmd-c` to `ctrl-c`.

This keeps the notebook interrupt shortcut available while allowing the
normal editor keybindings to handle:

- `cmd-c` for copy
- `cmd-x` for cut
- `cmd-v` for paste

inside notebook cell editors.
- This change is macOS-specific.

Release Notes:

- N/A

---------

Co-authored-by: dino <dinojoaocosta@gmail.com>

assets/keymaps/default-linux.json

@@ -1495,7 +1495,6 @@
       "ctrl-m": "notebook::AddCodeBlock",
       "ctrl-shift-m": "notebook::AddMarkdownBlock",
       "ctrl-shift-r": "notebook::RestartKernel",
-      "ctrl-c": "notebook::InterruptKernel",
       "escape": "notebook::EnterCommandMode",
     },
   },

assets/keymaps/default-macos.json

@@ -1633,7 +1633,6 @@
       "cmd-m": "notebook::AddCodeBlock",
       "cmd-shift-m": "notebook::AddMarkdownBlock",
       "cmd-shift-r": "notebook::RestartKernel",
-      "cmd-c": "notebook::InterruptKernel",
       "escape": "notebook::EnterCommandMode",
     },
   },

assets/keymaps/default-windows.json

@@ -1558,7 +1558,6 @@
       "ctrl-m": "notebook::AddCodeBlock",
       "ctrl-shift-m": "notebook::AddMarkdownBlock",
       "ctrl-shift-r": "notebook::RestartKernel",
-      "ctrl-c": "notebook::InterruptKernel",
       "escape": "notebook::EnterCommandMode",
     },
   },