improve progress indicators

[d-loose]

Minor UI updates:

• reduce stroke width of YaruCircularProgressIndicator as suggested by @Feichtmeier
• use YaruLinearProgressIndicator instead of LinearProgressIndicator
• add padding

	Dark	Light
Before
After

[jpnurmi]

@elioqoshi What do you think? I'm no designer but personally, I feel like the slim and rectangular progress bar fits this context better. :)

[d-loose]

I have to admit I like it better too - just added it for consistency with the rest of the yaru widgets :D

[Feichtmeier]

Maybe just add a percentage text left of the spinner?
I feel like two indicators are overkill

[jpnurmi]

A thinner spinner alone would be an immediate approval though! 😉

[d-loose]

I don't feel qualified to make any of these UX/UI decisions :D
@elioqoshi we know your time is precious and very limited, but I'd really appreciate some feedback on some of these questions (no need for any mockups):

• I'd like to use the Yaru widgets wherever possible, so I'd prefer using Yaru's linear progress indicator. But I also agree with @jpnurmi - the rounded bar looks weird when it spans the entire width of the page. Maybe we could simply add some horizontal margin?
• Are two indicators too many? I added the circular spinner to indicate that some work is still being done in the background, even if the linear progress indicator doesn't change for a couple of seconds. In general I prefer a visual indicator over a numerical percentage. What do you think?
  Something to keep in mind concerning the progress bars: the linear indicator displays the progress of the current step of the update (fwupd typically goes through multiple steps like downloading, verifying, reading, writing ... and reports a progress for each of those). There's no (easy) way to get the total progress (or does someone have a good idea?).

Thank you!