[BUGFIX] Install Tool modals won't depend on spinner

The Install Tool modals now fire up immediately after requesting a
module. The spinners are now loaded in parallel and don't block the
rendering of the modals anymore.

Resolves: #90750
Releases: master, 9.5
Change-Id: I05ef7da7917fe2633598d2c533fd7ecbe0284221
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63698


Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Frank Nägler <frank.naegler@typo3.org>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Frank Nägler <frank.naegler@typo3.org>