🤔 [QUESTION] Is `MetaOption.showLast` supported ?

### 🐛 Question description [Please make everyone to understand it]
I'm using an x axis of type `time` and I don't see the last time value shown when I set `showLast` to `true`. I also can't seem to find any references to it in the code, hence asking here. Any help appreciated.

### 💻 Link to minimal reproduction
```
xAxis: {
type: 'time',
mask: xAxisFormatter[timePeriod],
visible: true,
nice: false,
},
yAxis: {
grid: null,
},
meta: {
when: {
type: 'time',
mask: xAxisFormatter[timePeriod],
showLast: true,
range: [0.02, 0.98],
},
},
```

### 🏞 Expected result

Last date tick should have been displayed.

### 🚑 Any additional [like screenshots]

* **G2Plot Version**: antv/g2plot@2.4.5
* **Platform**: Chrome Version 97.0.4692.71 (Official Build) (arm64)

Start by reproducing the supplied time-axis configuration in G2Plot 2.4.5, focusing on the meta.when.showLast option and the expected final date tick. Check whether MetaOption.showLast is referenced or supported; done means confirming its behavior and reporting or correcting the discrepancy with a focused test if the project provides one.

Written by the indexing model from the issue text.