UI freeze exception to address three icon bugs

[Stuart Jaggers]

Following UI freeze, testing has discovered some icon bugs which could be fixed if an exception were granted. They are as follows.

1) Missing symlinks cause Gnome control centre to fall back to non-Yaru symbols for power settings and online accounts. The fallback symbols are thicker than the corresponding ones in Yaru and look out of place next to the others.

https://github.com/ubuntu/yaru/issues/1259 describes the issue and https://github.com/ubuntu/yaru/pull/1262 fixes it by adding the missing symlinks (both with screenshots).

2) A background process puts a poorly rendered, pixellated Yaru icon on the launcher when it errors. The cause was determined to be a symlink. Removing this causes the process to fall back to a pre-Yaru icon which is properly rendered. The proposed fix at this stage is merely to remove the symlink, because an old icon rendered properly is better than a Yaru one with pixels.

https://github.com/ubuntu/yaru/issues/1210 describes the issue and diagnosis (with screenshots) and https://github.com/ubuntu/yaru/pull/1267 fixes it.

3) A missing symlink causes Gnome Notes to use a non-Yaru icon when we have a Yaru icon for Notes. Adding the missing symlink would fix this.

https://github.com/ubuntu/yaru/issues/1180#issuecomment-472493170 describes the problem with screenshot.

All three issues could be fixed and fully tested with minimal risk simply by adding a small number of symlinks and removing one other. The benefit would be making the theme more polished in time for 19.04, rather than shipping it with three bugs that could be fixed. The changes have been tested by the Yaru team in branches of Yaru and the nature of these cosmetic changes makes them low risk. Because they're icon defects, they would otherwise be visible to all users of Ubuntu, and fixing them would have a good ratio of risk to benefit IMHO.

[Sebastien Bacher (seb128)]

Thank you for the report, those look like bugfixes which don't need an exception. Also that's rather a UI freeze exception than a feature one, see https://wiki.ubuntu.com/FreezeExceptionProcess#UserInterfaceFreeze_Exceptions , the documentation team should be let know about the request/changes

[Stuart Jaggers (jaggers)]

Ah, apologies for the error - thank you for the reply :)

[Sebastien Bacher (seb128)]

Seems like no-one had been contacting the documentation team, I did that now
https://lists.ubuntu.com/archives/ubuntu-doc/2019-March/020645.html

[Łukasz Zemczak (sil2100)]

This seems fine, please proceed ASAP.

[Jeremy Bícha (jbicha)]

https://launchpad.net/ubuntu/+source/yaru-theme/19.04.2