Fix#122454: Truncate the long terminal title

[suema0331]

This PR fixes #122454

[ghost]

All CLA requirements met.

[glaukiol1]

This does work correctly, for me this is approved

[Tyriar]

@aeschli thoughts on the changes to iconLabels? Should we make this span the baseline behavior instead?

[aeschli]

I don't like the changes to iconLabels very much:
I think its strange that iconLabels will create a span for just one of the text fragments and give it a class name label-text. And then there's a css rules in actionbar.css that happens to know about that css rule

I'd suggest to keep the changes local to the terminal title and not try to generalize this already in the iconLabels.

getSingleTabLabel creates a string and renderLabelWithIcons breaks it up again in a series of strings and icon spans.
Instead I would suggest to construct the label spans directly in updateLabel: use iconLabel.renderIcon to create the icon span create spans for label and descriptions and so on. That give you much better control over the dom nodes created and class names used.

I see that getSingleTabLabel is also used in the constructor but I wonder if the action label can really be used as it's more than just a label (label with the icon placeholders)

[aeschli]

see #122620 (comment)

[suema0331]

see #122620 (comment)

@aeschli
Thank you very much for your comment. 
I changed to construct the label spans directly in updateLabel using  iconLabel.renderIcon.

[Tyriar]

This got reverted in #128483