sublime: Don't map editor::FindNextMatch by default (#31029)

Closes: https://github.com/zed-industries/zed/issues/29535

Broken in: https://github.com/zed-industries/zed/pull/28559/files

Removes `editor::FindNextMatch` and `editor::FindPreviousMatch` from the
default sublime mappings. If you would like to use this, you will have
to add them to your user keymap. Reverts the previous behavior where
cmd-g / cmd-shift-g relies on the base keymap.

Linux:
```json
  {
    "context": "Editor && mode == full",
    "bindings": {
      "f3": "editor::FindNextMatch",
      "shift-f3": "editor::FindPreviousMatch"
    }
  }
```

MacOS:
```json
  {
    "context": "Editor && mode == full",
    "bindings": {
      "cmd-g": "editor::FindNextMatch",
      "cmd-shift-g": "editor::FindPreviousMatch"
    }
  },
```


Release Notes:

- Fixed a regression in Sublime Text keymap for find next/previous in
the search bar

assets/keymaps/linux/sublime_text.json

@@ -51,9 +51,7 @@
       "ctrl-k ctrl-l": "editor::ConvertToLowerCase",
       "shift-alt-m": "markdown::OpenPreviewToTheSide",
       "ctrl-backspace": "editor::DeleteToPreviousWordStart",
-      "ctrl-delete": "editor::DeleteToNextWordEnd",
-      "f3": "editor::FindNextMatch",
-      "shift-f3": "editor::FindPreviousMatch"
+      "ctrl-delete": "editor::DeleteToNextWordEnd"
     }
   },
   {