transform function that returns empty dataset causes issues with endLabel Formatter

### Version
5.2.0

### Reproduction link
[https://jsfiddle.net/x1hmnfwu/24/](https://jsfiddle.net/x1hmnfwu/24/)

### Steps to reproduce
Create a line series with an endLabel that has a formatter specified.
Point this series at a dataset that uses a transform function that can return no data points. (Imagine a filter that filters everything out, or a trend function that doesn't have enough data yet to return anything meaningful) is used for that series.
A per the jsfiddle, the line will not render (nor will any downstream rendering operations).

### What is expected?
The line should not appear, the endlabel should not render, an error shouldn't occur.

### What is actually happening?
echarts.min.js:45 Uncaught TypeError: Cannot read properties of undefined (reading 'length')

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I'm using a transform that results in an 'empty' dataset. This feels like something that could occur and needs to be supported. I've tried various workarounds such as an array with a null, an array with an object in it with value dimensions, but null values. Nothing appears to work :(