[TASK] Make attributes in AssetCollector optional

The AssetCollector does not necessarily need a filled array with
attributes for adding javascript or stylesheets. Make the $attributes
argument optional and default to an empty array.

Resolves: #90868
Releases: master
Change-Id: I7a6e5dad8724f36c0450d13cda853e90b1929e71
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63969


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Jonas Eberle <flightvision@googlemail.com>
Tested-by: Frank Nägler <frank.naegler@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Jonas Eberle <flightvision@googlemail.com>
Reviewed-by: Frank Nägler <frank.naegler@typo3.org>