[egui_plot] linked axes wrong scale/bounds

**Describe the bug**

Linked axes are inaccurately linked.
Compare the y axis of the top left and right plots in the screenshot.

There are a couple more fragility issues with axes linking but this appears to be a dominant one.

**To Reproduce**
Steps to reproduce the behavior:
1. https://www.egui.rs/#Demo
2. Select "Plot" from Egui demos
3. Select "Linked Axes" tab
4. Observe incorrect y axis scaling between top left and right plots (range in top left plot is larger)

**Expected behavior**
Correctly scaled and linked axis.

**Screenshots**

**Desktop (please complete the following information):**
- OS: Ubuntu
- Browser chrome
- Version 118.0.5993.70

**Additional context**
egui 0.23
egui_plot 0.23

* Still occurs in current master as of [fd75adb](https://github.com/emilk/egui/commit/fd75adb3a0e5f8ca373ac7e5e03f750e690ae87b)

* Still occurs as of [9ebfc9c](https://github.com/emilk/egui_plot/commit/9ebfc9c400f8835255754e6a2edb52ea77fab8c7), see https://emilk.github.io/egui_plot/