When importing settings from VS Code, the minimap is now enabled by
default (matching VS Code's behavior) even if the user hasn't explicitly
set minimap-related options in their VS Code settings.json.

Previously, if `editor.minimap.enabled` and `editor.minimap.autohide`
were absent from the VS Code config, Zed would leave minimap at its own
default ("never"). Since VS Code defaults to minimap on, this caused a
mismatch for users expecting their VS Code experience to carry over.

Closes #56297

Release Notes:

- Fixed apply VS Code minimap default when importing settings

Signed-off-by: Xiaobo Liu <cppcoffee@gmail.com>