[BUGFIX] Incomplete setup in ScriptViewHelperTest

Argument 'priority' is accessed in ScriptViewHelper
without fallback. This is fine, since fluid sets
arguments to default values in normal operation.

The test case however circumvents this argument
initialization, so a value has to be set in the test.

Resolves: #95527
Releases: master
Change-Id: If23fcd0c3632f662038815a8bd760f228abbeb92
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/71489


Tested-by: core-ci <typo3@b13.com>
Tested-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>