The CC license explicitly states that a work must be marked, but it does not say how this must exactly be done.
Creative Commons makes it clear that attribution can be conditioned by a specific context and medium.
In my opinion - yes - you can put all attributions in the About section. See how Google does it in Chrome or Mozilla in Firefox (or any other browser). They do a special "Open Source Licenses" section. For CC-BY licenses, this also applies, because these browsers contain content under these licenses.
See details in Firefox at about:license or chrome://credits.
You can do a thought experiment: you're writing a book.
You want to use Creative Commons-licensed graphics in this book.
Do you have to list the CC licenses on every instance of each graphic? Can you just make yourself a copyright section somewhere at the end or beginning and put that in there?
You must do this within one work or materials attached directly to that work (e.g. in the description of a video).
Since you save this information in the app and use the icons in the app, it's a bit like writing the information elsewhere in the book (e.g. at the end of the book). If this argument appeals to you, I would like to point out that programs are often copyrighted "as literary works" (depending on the jurisdiction).
If you still have any doubts, you can check out the creative commons wiki.
If you have any other questions feel free to ask.
This is not legal advice
