### Godot version

8449592d92eaeef990f5502b419d491ee3eeb7a6

### System information

Windows 11

### Issue description

Zooming in the script editor on an empty script freezes the entire editor for a few seconds, but if the file is large then it freezes for 4-5 seconds (which is unacceptable). Looks like a recent regression.

### Steps to reproduce

Just zoom in/out on the large script file.

### Minimal reproduction project

N/A
ERR_FAIL_INDEX((int)p_spacing, 4);
	ShapedTextDataFallback *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND(!sd);
	MutexLock lock(sd->mutex);
	if (sd->extra_spacing[p_spacing] != p_value) {
		if (sd->parent != RID()) {
			full_copy(sd);
		}
		sd->extra_spacing[p_spacing] = p_value;
		invalidate(sd);
	}
}
int64_t TextServerFallback::_shaped_text_get_spacing(const RID &p_shaped, SpacingType p_spacing) const {
	ERR_FAIL_INDEX_V((int)p_spacing, 4, 0);
	const ShapedTextDataFallback *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_V(!sd, 0);
	MutexLock lock(sd->mutex);
	return sd->extra_spacing[p_spacing];
}
int64_t TextServerFallback::_shaped_get_span_count(const RID &p_shaped) const {
	ShapedTextDataFallback *sd = shaped_owner.get_or_null(p_shaped);
	ERR_FAIL_COND_V(!sd, 0);
	return sd->spans.size();
}
Variant TextServerFallback::_shaped_get_span_meta(const RID &p_shaped, int64_t p_index) const {