fix(toast): remove the interim element from the list before closing element

[marosoft]

Check if the interim element is valid before proceeding.

Fixes #10715

PR Checklist

Please check that your PR fulfills the following requirements:

• The commit message follows our guidelines
• Tests for the changes have been added or this is not a bug fix / enhancement
• Docs have been added, updated, or were not required

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Enhancement
[ ] Documentation content changes
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

At the moment the interim element is being removed from the list after new hideAction promise is created for it. In addition no extra check is made for the interim object before it is used.
This is causing an error as undefined object is trying be accessed.
Issue Number: #10715

What is the new behavior?

The interim element is removed from the list before the closeElement method is called.
An extra check is added at the beginning of that method to make sure the interim element is a valid object.

Does this PR introduce a breaking change?

[ ] Yes
[X] No

Other information

[Splaktar]

This looks good to me.

Can you please add a simple unit test that verifies this fix?

[Splaktar]

@marosoft I'd like to get this into 1.1.11 which I hope to release soon. Can you please add a quick unit test for this so that I can get it merged?

[marosoft]

@Splaktar sorry for a delay. I tried adding a small unit test in the interim element component but I couldn't reproduce the issue. I am not that much familiar with the internals and I might doing something wrong. I will try to spend some time tomorrow on it.

[Splaktar]

I am also unable to reproduce this issue with a unit test. I tried an $mdToast test that looks just like the original issue's CodePen, but it doesn't throw an exception.