fix the default config for explore

[amtoine]

according to

nushell/crates/nu-explore/src/commands/table.rs

Lines 132 to 135 in 0674d49

	"table.show_cursor" => {
	self.settings.show_cursor = bool_from_str(&value);
	self.settings.turn_on_cursor_mode = true;
	}

the config should be called $env.config.explore.table.show_cursor instead of the current $env.config.explore.table.cursor 😮

this PR fixes this in the default config.

[fdncred]

good catch!