Fix missing styling from various icon container locations

[mjcrouch]

This PR fixes fixes #87668 - in which strikethrough is missing from scm provider resources

Note that there are 7 more references in various css files to .monaco-icon-label-description-container - which no longer appears to exist in the code. I have not yet analyzed whether they should also be updated to the new classes. (see below)

[mjcrouch]

I notice that the tests failed due to hygiene checks, but this seems to have been caused by the update to TS 3.8 about an hour ago 464ee36 and is not related to the PR...

[mjcrouch]

Having looked through the other instances a bit more I believe they should all be updated as well - haven't managed to actually produce the right conditions yet though.

For example suggest.css implies deprecated items should have strike through, but functions don't appear to have the deprecated tag applied to them when I make them deprecated via the comments, and as such the deprecated class isn't applied. (Probably something I'm doing wrong).

A couple of them refer to previous minor styling issues in the tab header, I wasn't able to reproduce the actual original issues with the incorrect css - nevertheless by inspecting the elements, the current css is clearly not applied as intended

[msftclas]

All CLA requirements met.

[mjcrouch]

I've updated the PR to update all the styles that had the incorrect class name.

I was able to prove that deprecated strikethrough was broken by modifying the sample completion-sample extension.

I did clearly see that the correct overflow / text-overflow styles were applied to tabs following my change - though I couldn't see any visible difference from when they did not have the correct styles.

Same for the quick open dialog and the custom view tree (e.g. the npm scripts view) - flex: 1 was not applied, but I could not see any visible difference when it was applied.

I haven't worked out how to produce an element with .remote-help-tree-node-item-icon

(I seem to be good at timing my submissions badly, as the tests failed again due to an unrelated issue)

[joaomoreno]

Great PR! Thank you!