improve "box icon" tooltip on certain SVGs

[petersutter]

What happened:
When hovering over the connection status or over the certified kubernetes logo in the shoot list, the tooltip "box icon" is shown.

dashboard/frontend/src/components/icons/GIconBase.vue

Lines 16 to 19 in 1c7c437

	<title
	:id="iconName"
	lang="en"
	>{{ iconName }} icon</title>

What you expected to happen:
Show proper tooltip. When the GIconBase component is used, also the icon-name property should be passed so that the default "box" is not used.
We should remove the title if no icon-name is passed to prevent showing an unnecessary tooltip.

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know:

Environment: