[Stepper] Invalid connection line rendering when one step is rendered

[yanmariomenev]

Describe the bug

When only one step is provided to the component, it also draws a line to a nonexistent second step, which shouldn't happen. For example, this is handled well in Kendo UI for jQuery:

https://dojo.telerik.com/IbIgiFOd

To Reproduce

Provide only one step to the component or open the following example:
https://codesandbox.io/p/sandbox/clever-danilo-qlklv8?file=%2Fsrc%2Fapp%2Fapp.component.ts%3A15%2C5-15%2C22

Screenshot