[BUG] `(org-agenda-list)` doesn't respect the `org-agenda-start-day` when `org-agenda-span` is equal to 7. [9.6.1 (release_9.5.5-1519-gaa2249 @ /home/rmnull/lab/libre/org-mode/lisp/)]

[rmnull@posteo.net]

Hi, This is first my first bug report to org-mode. So I would like to 
start by thanking
everyone involved for making this life enhancing drug a reality. It's 
one of the rare software which
actually does what i mean. It's wonderful :cheers:

* One Line summary
    `org-agenda-list` shows the week agenda list, instead of respecting 
the org-agenda-start-day when the org-agenda-span is 7.

* A Little detailing about the bug and reproduction steps
When I run this, `org-agenda-list` lists the previous 2 days, current 
day and the next 2 days.
#+BEGIN_SRC emacs-lisp
   (setq org-agenda-span 5)
   (setq org-agenda-start-day "-2d")
   (org-agenda-list)
#+END_SRC
Which is quite nice because that's an expected behavior.

However when I run a similar code,
#+BEGIN_SRC emacs-lisp
   (setq org-agenda-span 7)
   (setq org-agenda-start-day "-3d")
   (org-agenda-list)
#+END_SRC
It lists the current week, start from the beginning of this week.
Instead I was expecting org to list previous 3 days, current day and the 
next 3 days.

The output looks like this
#+BEGIN_QUOTE
Monday     20 February 2023 W08
Tuesday    21 February 2023
Wednesday  22 February 2023
Thursday   23 February 2023
Friday     24 February 2023
Saturday   25 February 2023
Sunday     26 February 2023
#+END_QUOTE

whereas it should have looked like

#+BEGIN_QUOTE
Thursday   23 February 2023
Friday     24 February 2023
Saturday   25 February 2023
Sunday     26 February 2023
Monday     27 February 2023 W09
Tuesday    28 February 2023
Wednesday   1 March 2023
#+END_QUOTE

* Where exactly did you test this behavior?

I tested it on the emacs launched by `make repro` command of the 
org-mode,
the git was pointing to `main` branch(commit-id: aa2249787).

Emacs  : GNU Emacs 28.2 (build 2, x86_64-unknown-linux-gnu, GTK+ Version 
3.24.34, cairo version 1.16.0)
  of 2022-09-14
Package: Org mode version 9.6.1 (release_9.5.5-1519-gaa2249 @ 
/home/rmnull/lab/libre/org-mode/lisp/)


If any information has been left out, do let me know.

Thanks,
rmnull.