### Godot version

v4.0.beta10.official [d0398f62f]

### System information

Windows 22H2, Compatibility, GeForce GTX 550 Ti

### Issue description

Multiple lines of error messages are copied without line breaks:
The script editor's error panel shows:
```
Line 6:Expected parameter name.
Line 6:Expected closing ")" after function parameters.
Line 6:Expected ":" after function declaration.
```
But selecting and copying them `ctrl c`, copies them without line breaks:
```
Line 6:Expected parameter name.Line 6:Expected closing ")" after function parameters.Line 6:Expected ":" after function declaration.
```


### Steps to reproduce

- start Godot
- open the attached project
- open the script `Node2D.gd`
The status bar shows an error message.
- click on the red circle with an x in it, and the number 3 to the right of the circle.
The script editor's error panel shows three messages:
>Line 6:Expected parameter name.
Line 6:Expected closing ")" after function parameters.
Line 6:Expected ":" after function declaration.

- select all three lines, and copy them `ctrl c`
- in the script editor, click on the empty line 12 to place the cursor there.
- paste `ctrl v`

### Expected
The copied lines should be pasted on three lines, as they appeared in the error panel.

### Observed
There are no line breaks, they appear on the same line:
```
Line 6:Expected parameter name.Line 6:Expected closing ")" after function parameters.Line 6:Expected ":" after function declaration.
```


### Minimal reproduction project

[issue, error messages copied without line breaks.zip](https://github.com/godotengine/godot/files/10361376/issue.error.messages.copied.without.line.breaks.zip)

code_editor = memnew(CodeTextEditor);
	code_editor->add_theme_constant_override("separation", 2);
	code_editor->set_anchors_and_offsets_preset(Control::PRESET_FULL_RECT);
	code_editor->set_code_complete_func(_code_complete_scripts, this);
	code_editor->set_v_size_flags(SIZE_EXPAND_FILL);
	code_editor->get_text_editor()->set_draw_breakpoints_gutter(true);
	code_editor->get_text_editor()->set_draw_executing_lines_gutter(true);
	code_editor->get_text_editor()->connect("breakpoint_toggled", callable_mp(this, &ScriptTextEditor::_breakpoint_toggled));
	connection_gutter = 1;
	code_editor->get_text_editor()->add_gutter(connection_gutter);
	code_editor->get_text_editor()->set_gutter_name(connection_gutter, "connection_gutter");
	code_editor->get_text_editor()->set_gutter_draw(connection_gutter, false);
	code_editor->get_text_editor()->set_gutter_overwritable(connection_gutter, true);
	code_editor->get_text_editor()->set_gutter_type(connection_gutter, TextEdit::GUTTER_TYPE_ICON);
	warnings_panel = memnew(RichTextLabel);
	warnings_panel->set_custom_minimum_size(Size2(0, 100 * EDSCALE));
	warnings_panel->set_h_size_flags(SIZE_EXPAND_FILL);
	warnings_panel->set_meta_underline(true);
	warnings_panel->set_selection_enabled(true);
	warnings_panel->set_context_menu_enabled(true);
	warnings_panel->set_focus_mode(FOCUS_CLICK);
	warnings_panel->hide();
	errors_panel = memnew(RichTextLabel);
	errors_panel->set_custom_minimum_size(Size2(0, 100 * EDSCALE));