[BUGFIX] Remove loader placeholder in SvgTree if search term is empty

In a case, where the search term is empty (by removing the search term
manually for example) and a node is currently selected, the loader
placeholder is now removed. This is the only case, where the method
"resetFilter" is not called.

Resolves: #94464
Releases: master
Change-Id: Iad0deca5c9793cd0823d62c3864bc63e0fb40288
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70182


Tested-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>