[TASK] Install Tool: Remove misleading password hint

There is no default install tool password any more
thus we need to change the login message text.

Releases: 6.2
Resolves: #52808
Change-Id: I02b435b951c582a1e1ff466ca9bd8e5e157141e3
Reviewed-on: https://review.typo3.org/24740
Reviewed-by: Wouter Wolters
Reviewed-by: Stefano Kowalke
Tested-by: Stefano Kowalke
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn