### Godot version

4.1

### System information

Windows

### Issue description

Being able to have multiple cursors similarly to vscode is a great feature, however it's only possible to add carets, not remove them. By left clicking you can remove all extra cursors but you cannot remove a specific one so after selecting multiple lines a single missclick, you have to reselect them all again. Looking at the original pr there was a remove_caret function added so it would make sense to be able to remove carets when clicking again, like in vscode.

![image](https://github.com/godotengine/godot/assets/19669673/3867c00e-9faa-4429-9c6d-f2d6d3883044)


### Steps to reproduce

- Alt click to add multiple carets
- Alt click on the same position again
- Nothing happens

### Minimal reproduction project

N/A
if (color != previous_color) {
									characters--;
									j--;
									if (str[j] == '\t') {
										tabs -= minimap_tab_size;
									}
								}
							}
							if (characters > 0) {
								previous_color.a *= 0.6;
								
								int chars = MAX(0, (j - (characters - 1)) - (whitespace ? 1 : 0)) + 1;
								int char_x_ofs = indent_px + ((xmargin_end + minimap_char_size.x) + (minimap_char_size.x * chars)) + tabs;
								if (rtl) {
									RenderingServer::get_singleton()->canvas_item_add_rect(ci, Rect2(Point2(size.width - char_x_ofs - minimap_char_size.x * characters, minimap_line_height * i), Point2(minimap_char_size.x * characters, minimap_char_size.y)), previous_color);
								} else {
									RenderingServer::get_singleton()->canvas_item_add_rect(ci, Rect2(Point2(char_x_ofs, minimap_line_height * i), Point2(minimap_char_size.x * characters, minimap_char_size.y)), previous_color);
								}
							}
							if (out_of_bounds) {
								break;
							}
							if (str[j] == '\t') {
								tabs += minimap_tab_size;
							}
							previous_color = color;
							characters = 0;
						}