### Godot version

4.0 dev Beta 10

### System information

MacBook Pro M1 Max

### Issue description

After I imported font.ttf file and move it from one folder to another under ://res godot suddenly crashed, and it still crashes after restart.

### Steps to reproduce

Import some font.ttf file and try to move into different folder

### Minimal reproduction project

N/A
FontFallback *fd = font_owner.get_or_null(p_font_rid);
	ERR_FAIL_COND(!fd);
	MutexLock lock(fd->mutex);
	Vector2i size = _get_size(fd, 16);
	ERR_FAIL_COND(!_ensure_cache_for_size(fd, size));
	fd->weight = CLAMP(p_weight, 100, 999);
}
int64_t TextServerFallback::_font_get_weight(const RID &p_font_rid) const {
	FontFallback *fd = font_owner.get_or_null(p_font_rid);
	ERR_FAIL_COND_V(!fd, 400);
	MutexLock lock(fd->mutex);
	Vector2i size = _get_size(fd, 16);
	ERR_FAIL_COND_V(!_ensure_cache_for_size(fd, size), 400);
	return fd->weight;
}
void TextServerFallback::_font_set_stretch(const RID &p_font_rid, int64_t p_stretch) {
	FontFallback *fd = font_owner.get_or_null(p_font_rid);
	ERR_FAIL_COND(!fd);
	MutexLock lock(fd->mutex);
	Vector2i size = _get_size(fd, 16);
	ERR_FAIL_COND(!_ensure_cache_for_size(fd, size));
	fd->stretch = CLAMP(p_stretch, 50, 200);
}
int64_t TextServerFallback::_font_get_stretch(const RID &p_font_rid) const {