[BUGFIX] Use `spinner-circle` in `DeferredAction`

Due to color changes in the notifications, the spinner used in deferred
actions was barely visible since then. This patch changes the icon
identifier to `spinner-circle`, showing a darker spinner again.

Resolves: #101399
Releases: main, 12.4
Change-Id: I1f3f8fa83b4c68103376ae154693c4381ce75c25
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80103


Reviewed-by: Alexander Schnitzler <git@alexanderschnitzler.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Alexander Schnitzler <git@alexanderschnitzler.de>