Revert "core/mount: fail early if directory cannot be created"
This reverts commit e4de58c8231e47509ffeb3aa47620ca42f22d7f6.
If mkdir() fails and the path does exist, then the later mount
command fails anyway. Hence, it is not necessary to fail here.
Fixes #24120.
(cherry picked from commit e5e6b7c225987551ebda14d2d7feadb66a64fb3c)